Locating Extremists Where They Strike: Ideological and Geographic Influences on Terrorist Target Selection

The posts below are brief summaries of 14-week research projects designed and carried out by our student team. tPP plans to release the full studies as peer-reviewed publications in the future.

Locating Extremists Where They Strike: Ideological and Geographic Influences on Terrorist Target Selection

Isabel Bielamowicz and Kayla Groneck








The purpose of our research was to identify the relationships between geographic location, ideological affiliation, and physical target for cases of politically motivated violence coded in the Prosecution Project’s (tPP) dataset. We contended that population density will be reflected in clusters of attack locations, and that higher population urban hubs will likely have greater diversity of both ideology and target type, with more obvious trends being revealed in lower population regions. Furthermore, we proposed that Leftist affiliated attacks and prosecutions will see higher concentration on the West and East coasts with targets focused on Private Sites; whereas Rightist affiliated attacks and prosecutions will see greater presence in the South and the Midwest, with target type focused on Religious Institutions, Federal Sites, and Individual Person(s). Additionally, we hypothesized that Salafi/Jihadist/Islamist attacks will be nearly exclusive to high population density urban areas with target type focused on Federal Sites and Public Sites.

Methodologically, descriptive statistics were employed to reveal that over half of our selected sample is composed of those sharing Rightist ideology acting uniformly across the United States; that Leftists act predominantly in the West, targeting Private Sites almost exclusively; and that Salafi/Jihadist/Islamists act across the spread of the country, but most commonly in high density areas. We found that mapping through GIS software augmented our statistical findings by visualizing the spread of attacks and prosecutions in our dataset by ideological affiliation. Based on our findings, we concluded that geography is helpful in defining political violence in the United States to the extent that is has strong correlations to the ideological affiliation of a defendant. Ultimately, this relationship between geography and ideology and the relationship between ideology and target type culminate in an understanding of the geographical spread of target selection employed by delineated ideologies across the United States for political violence attacks and prosecutions.

The following datatable shows the two most frequent physical targets selected by the four most common ideological affiliations found in our selected sample (N611 set) divided by circuit court regions. The most prominent findings of this research are that Rightist attacks and prosecutions composed over 50% of our sample; Salafi/Jihadist/Islamists were over four times more likely, than is proportional to the population, to attack and be prosecuted in the 2nd circuit; that Leftists were most likely to attack and be prosecuted in the 9th circuit.

Because this research is based on a the tPP dataset, which tracks prosecutions rather than attacks, it would be negligent not to mention that many of the cases included in the N611 set have multiple co-defendants for singular events. Without this clarification, some data points may be misleading. As it stands, our hypotheses regarding this research were predominantly correct for geographic concentrations of ideology and the most frequent target types selected by the most prominent ideological affiliations within the given dataset. Conclusively, the most prevalent ideological affiliations (composing >10% of the N611 dataset) for attacks on physical targets within the United States which have resulted in prosecutions are as follows: Rightist: government-focused, Rightist: identity-focused, Leftist: eco-animal focused, and Salafi/Jihadist/Islamist.

The geographic sprawl of these ideologies across the United States varies categorically based on a set of factors including population density, spatial and temporal considerations, and target type.

This research identifies the relationships between geography, ideology, and target type as related to political violent attacks and prosecutions, and ultimately concludes that ideology has a stronger direct relationship to physical target selection than geography. The extent to which the geographic sprawl of persons having shared ideological affiliation which motivated political violence is not predictive of future attacks or prosecutions; however, it is indicative of trends which may continue in the future. Trends in geographic concentration of ideologies are very useful as they aid both in understanding patterns in selection frequency of classifications of physical targets and in predicting – to a degree – the regions in which certain physical target classes are most at-risk or in which regions individuals of certain ideological affiliations are likely to be indicted for targeting them.

The Influence Ideological Affiliation Can Have on Length of Prison Sentence

The posts below are brief summaries of 14-week research projects designed and carried out by our student team. tPP plans to release the full studies as peer-reviewed publications in the future.

The Influence Ideological Affiliation Can Have on Length of Prison Sentence

Monica Gomes

When it comes to the ideological affiliation of a criminal and its influence on a potential or carried through crime with a focus on material support charged crimes, the length of sentence can seemingly be predicted. Not predicted in a way that we are able to figure out what the exact length of sentence will be, but perhaps a direction it may go. The findings for this research study signify just this. To easily compare the data, I compiled a chart of basic math calculations including the median, mode, mean, and range. The categories where the crimes are not ideologically affiliated or are unclear of the affiliation, if there is one, produced the lowest values in terms of length of sentence compared to any other ideological affiliation. This is possibly due to the fact that these crimes in particular are not associated with any large entity or terrorist organization with the potential to endanger the greater society.



Ideological affiliations that do pose as a potentially larger risk are the rightist and leftist affiliations. Although there are separate categories within the leftist and rightist ideologies, for this study I decided to combine all leftist and all rightist ideologies because the number of cases included in the subject sample were very low and putting them together would produce more significant results. The values that were calculated for this dataset to observe showed that the rightist and leftist ideological affiliations were not the highest but not the lowest values.

These two affiliations traded off with one being higher than the other and then being the lower value of the two. Therefore, that places these affiliations at similar outcomes to each other. The highest values lie within the nationalist- separatist and salafi/jihadist/islamist affiliations with nationalist- separatist having slightly higher values overall. The only exception to this portion of the data is that the greatest number for length of sentence among the ideological affiliations is salafi/jihadist/islamist, however, the highest average for lengths of sentence is nationalist- separatist.

A potential factor that goes into this result is that there are only eighteen cases that are identified as nationalist- separatist while there are two hundred and forty-three salafi/jihadist/islamist. The nationalist- separatist, salafi/jihadist/islamist, and leftist ideological affiliations have a sentence length of zero for their least number of months. This is due to those cases being acquitted but the case still being included into the original tPP database. Criminal charges against perpetrators who engage in material support and are prosecuted for that crime is incredibly complicated and prosecutors must consider many different factors.

First of all, previously prosecuted crimes must be taken into account as well as the intent of the perpetrator. High profile criminal charges call for a more severe sentencing, which becomes increased even more with high intensity previous crimes. Another important factor is intent, this could be an intention as part of a terrorist organization or just the intent to promote or support one. These factors are considered into the criminal cases included in this dataset that ultimately determine and explain the trends shown through the collected data.

The subject and focus of this research is an important extension to the wider field of study of crimes throughout the United States, with an additional lens looking at terrorism crimes. Crime, specifically incarceration, has been and is a prevalent distinction that sets the United States and other nations apart which leaves people curious as to why this is the case. Because of that, endless amounts of research have been done to unveil the possible meanings and reasons behind this fact.

This study is able to contribute to that knowledge and give an explanation to those high incarceration rates. The ability to apply previous findings and knowledge to this less recognized area of crime studies can be of practical use when creating future policies regarding the subject. More specific data and observation of that data, particularly speaking towards ideological affiliation and length of sentence, will help redirect or reevaluate current policies and what producers can do to create a more just system.

The hypothesis created in the proposal wanted to examine material support cases pre-9/11 and post-9/11. In doing this, the research would have found trends and themes from the data to observe any disparities between ideological affiliation and if that was a determiner for the proposed length of sentence of the perpetrator. This kind of data would have been able to make assumptions and locate any forms of discrimination within the justice system against individuals who possessed certain beliefs and if it has been a persistent issue. The justice system supposedly does not have any prejudices against certain individuals and purely look at the facts when determining a length of sentence, but as we know, human error is an inevitable factor when dealing with these types of situations.

Bias and emotions, as well as opinions, are factors that will be included when involved in the justice system while dealing with crime cases whether it is intended or not. The original hypothesis wanted to explore this concept to evaluate and analyze if these types of injustices occurred, however, I had to reroute my research topic because there weren’t enough cases pre-9/11 to build a strong enough database to compare to post-9/11 crime cases. I will say that in regard to material support, there are many salafi/jihadist/islamist ideologies, which is expected because this group of individuals is heavily associated with larger groups of people, or organizations, with the intent of material support for their plans to carry out action.

The world of crime and criminal studies is such a large entity that has an unlimited amount of data and information that it is difficult to find an area of concern that hasn’t been researched already. Today’s society comes with an enormous list of issues and occurrences that are considered disturbing to the majority of society which provides researchers with the resources to examine and create their own inferences and their own basis of knowledge that they can eventually share with others. In relatively recent years, terrorism studies have been more thoroughly explored due to the occurrences that took place on September 11, 2001.

Crimes that  are committed who are in affiliation with a foreign terrorist organization are not dealt with lightly and it has been a mission to eradicate any forms of associations with these organizations throughout the United States. Because of this incident, terrorism crimes have been under the eye of many researchers who haven’t left much room for different thought. In exploring different areas of this field in particular, I think it would be important to look at mapping as a methodology to locate where future crimes may occur based on tactic and the perpetrator’s ideological affiliation. I believe that these components to a crime can say a lot about where others may target next and how they will go about doing their crime. It could possibly prevent future occurrences by recognizing the patterns that previous criminals have pursued.

Age and Ideological Affiliation in Terrorism: As Reported in tPP

The posts below are brief summaries of 14-week research projects designed and carried out by our student team. tPP plans to release the full studies as peer-reviewed publications in the future.

Age and Ideological Affiliation in Terrorism: As Reported in tPP

Preet Patel

The results of my research represent various statistics regarding age, ideological affiliation, and number of people killed per attack in the Prosecution Project database. The graphs representing the statistical analysis that I ran reflect some averages and ranges that should be considered in understanding the subset of data that I finalized for my research.

Based on these findings, we can make conclusions regarding the average age of an attacker, the average number of people killed per attack, and the most common ideological affiliations for cases that resulted in one or more deaths per attack.

This research fits into the wider field of study in the Prosecution Project in its ability to offer understandings as to who commits certain acts of terrorism, as well as how and why those people committed those acts.

Further, in accordance with a variety of theoretical frameworks, conclusions can be drawn to further elaborate on why individuals commit terrorist acts and how these acts can be deterred by people in positions of authority such as police officers, prosecutors, judges, etc.

For future study of this material, I would first recommend sticking with a smaller subset of the full Prosecution Project database. This is beneficial because it allows researchers to analyze the data in a more detailed manner and reduces potential confusion, misinterpretation, and/or overlooking of data and details. Additionally, I would suggest considering multiple secondary coders depending on the type of research and analysis one is planning on conducting.

Gender, Jail, and Injustice: Gender Interaction Effects on Judicial Sentencing Rhetoric

The posts below are brief summaries of 14-week research projects designed and carried out by our student team. tPP plans to release the full studies as peer-reviewed publications in the future.

Gender, Jail, and Injustice: Gender Interaction Effects on Judicial Sentencing Rhetoric

Maddie Weaver & Alexandria Doty








The following report analyzes court documents that correspond with the Prosecution Project’s dataset as of mid-April 2019. There is a clear and statistically significant relationship between gender and sentence lengths, but there are no prevailing theories on the reasons behind this correlation. The purpose of this study was to find out why defendants that have similar backgrounds in all other coded variables still face different sentences, as decided by a judge through the federal sentencing guidelines. There is no written record of how a judge uses the guidelines or any other logic for that matter to show how they reach the sentence that they do. We wanted to find the patterns between how sentences are given and connect it with the rhetoric that judges use during sentencing hearings for both men and women. It was hypothesized that, when analyzing judge’s sentencing transcripts, there will be gender-based biases within the rhetoric.

The final sentencing hearing is focused on giving both the prosecuting witness(es) and the defendant a space to express the effects of the crime and the trial on their lives. Federal judges are elected or appointed to be impartial upholders of the law, but as shown by the creation of the Federal Sentencing Guidelines, impartiality is something not commonly achieved. Thus, we believed that we would be most likely to find consistent rhetoric used by judges by utilizing sentencing hearings. Our study looked at the transcripts published from these hearings, as well as other documentation related to sentencing such as memorandums and judgements, in order to collect data of the lexicon and rhetoric used.

The hearing transcripts from 54 women within tPP database were analyzed and then compared to a comparable sample of men to look for major differences or patterns that were present. We analyzed these documents through AntConc, a corpus linguistic analysis software that allows us to look into patterns present in large selections of text and found many interesting patterns.

One interesting finding was through another software we used, R, that showed men’s memorandums being shockingly similar to women’s judgments when it came to the ratio of positive and negative words used throughout the document. Similarly, men’s judgments were very similar to women’s memorandums ratio of positive to negative words. While all had significantly more negative than positive words, the men’s judgments had the most positive to negative ratio, just exceeding the half and half point.

With more time and expertise of R and other sentiment analysis packages, this research could dive deeper into finding what these patterns describe. If bias is found with closer examination by more advanced sentiment analysis, judges could be trained and better understand their bias as well as the bias of the Federal Sentencing Guidelines that could be leading men to receive disproportionally longer sentencing lengths. This could then be examined not only for gender but also inclusive of variables like race.

An Exploratory Dive into the Dark Network Links of Far-Right tPP Cases

The posts below are brief summaries of 14-week research projects designed and carried out by our student team. tPP plans to release the full studies as peer-reviewed publications in the future.

An Exploratory Dive into the Dark Network Links of Far-Right tPP Cases

Meg Drown

There has been a mass movement by far-right extremists to dark web social media platforms and the use of cryptocurrencies as a means to crowdsource. This move has largely been due to the initiatives of big tech companies to stymie the current of extremist content on their websites by removing users who express extremist views or are otherwise connected to extremist organizations. Many on the far-right have publicly renounced Facebook, Twitter, and other tech companies claiming that their actions to remove extremist content, especially that iterated from the far-right, infringes on Americans’ right to free speech [1].

Although there are detailed user agreements that place constraints on the content that is broadcast by users, prohibiting the kind of insulting and hateful speech that is often expressed by those on the far-right, leaders and organizers on the far-right have gained momentum by politicizing this phenomenon. However new sites have arisen to paradoxically give far-right extremists a “safe haven” to express their views. The creator of social media platform Gab, has told media outlets that the purpose of Gab was to create an online platform specifically for conservatives and the far-right, whom he believes have been treated unfairly by big tech. The site’s lackadaisical regulations on what would normatively be considered hate speech and its targeted advertising towards conservatives have combined to create the perfect storm, or what has been described as a “hate-filled echo chamber full of racism and conspiracy theories” [2].

Likewise, 8chan, an imageboard and offshoot of 4chan, is another well-known site that harbors extremist content. Purportedly, the manifesto released by 28-year-old Brenton Tarrant, the man who murdered 50 Muslims at two mosques in Christchurch, New Zealand was circulated via 8chan and fell into the hands of another impressionable extremist. John Earnest, a 19-year-old who has been indicted on 109 hate crime charges, carried out an attack on a synagogue in early May leaving one dead and three injured. According to a Vox article detailing the apparent perils of 8chan, Earnest was inspired to carry out the attack, in part, due to the radical ideology outlined in Tarrant’s manifesto [3].

Fintech has pursued similar action against extremist users. Mainstream digital fundraising sites such as PayPal and Amazon, have been proactively identifying and denying access to those users utilizing their sites to fundraise for nefarious purposes. Richard Spencer and prominent voices on the far-right reveled at the spectacularity of Bitcoin to fundraise for their unsettling online platforms. Bitcoin and other cryptocurrencies are unique due to their peer-to-peer (P2P) transactional features. It is, in part, due to this feature that makes it easy to hide under the guise of anonymity while extorting money for various purposes [4]. Though the apparent anonymity benefits of Bitcoin and other cryptocurrencies have been cited by law enforcement and those using Bitcoin as a means to fundraise as the defining feature of the platform, scholars have asserted that Bitcoin is one knock below anonymous. Rather, Bitcoin and many of its crypto counterparts are pseudonymous due to endpoint identification in straightforward transactions.

An ambition of many open-source intelligence analysts is to be able to identify and track the financial networks of far-right actors. Certainly, open-source intelligence analysts have been highly successful at identifying traditional transactional networks and, recently, crypto transactional networks. John Bambenek, an open-source intelligence researcher and professor of cybersecurity at the iSchool in Illinois, does just that [5]. Specifically, Bambenek tracks the donations received by white nationalist BTC wallets, the amount spent, and their balance, which he records in a daily wallet summary report via his Twitter account called Neonazi BTC Tracker (@NeonaziWallets) [6]. Bambenek also records whenever a withdrawal or a substantial donation is made to one of the white nationalist BTC wallets in a separate tweet. For all of the apparent anonymity benefits of using BTC, highly-skilled computer scientists are able to identify and track specific BTC wallets using mathematical algorithms and the fact that the BTC transaction log is public by design.

Keeping in mind tPP while researching the shift of far-right actors to cryptocurrencies and dark web platforms, it was an ambition of mine to be able to identify individuals who occur in tPP that exist in a crypto transactional network with some prominent members of the far-right that have rose to prominence in recent years, and have, in fact, gained traction in the Bitcoin and dark web realms. However, due to my limited capabilities in being able to identify users who send donations via Bitcoin to these prominent far-right actors and the sheer volume of transactions that occur between their accounts, I found it an improbable task to carry out in a limited amount of time.

However, I did find that individuals in tPP who are coded as Rightist: Identity-focused under the variable Ideological Affiliation, especially those occurring after the Charlottesville “Unite the Right” rally in 2017 had maintained a presence on dark web forums and were, perhaps, inspired by extremist media purveyed on these forums. Wanting to delve deeper into the dark web links of individuals in tPP, I took an exploratory sample of those coded as Rightist: Identity-focused occuring after 12 August 2017. I created a link analysis which identified how various actors in the exploratory sample connected with one another.

To do so, I collected open-source data on the individuals via court documents, newspaper articles, and examination of dark web content that had been released online. Though the results were rather underwhelming – most individuals who were linked to one another were linked through organizational ties – I did find that several members of my exploratory sample had maintained ties with prominent far-right organizers, such as Richard Spencer and Eli Mosley, or others in tPP who had carried out high-profile attacks such as Dylann Roof and Robert Bowers. In fact, Bowers purportedly decried the prosecutions of various members of the Rise Above Movement (RAM), described as a “a Southern California-based racist fight club” [7], who appeared in the exploratory sample and had allegedly interchanged with the leader of RAM, Robert Rundo, via Gab.

Though the subject sample was small and the findings marginally supportive of a dark web network that exists between tPP individuals, my paper revealed that there are demonstrable links between actors on the right through dark web social media platforms such as Gab, Discord, and 8chan. Further studies can and should be carried out in order that we can better understand how individuals occurring in tPP interact and position themselves in the far-right movement through dark web participation.


[1] Kirkland, “Relegated To Fringe Platforms, White Nationalists Stuck In Own Echo Chamber”; “Big Tech, the Alt-Right and the Unknown Future of the Internet”; “Inside the Hate-Filled Echo Chamber of Racism and Conspiracy Theories | Media | The Guardian.”

[2] “Inside the Hate-Filled Echo Chamber of Racism and Conspiracy Theories | Media | The Guardian.”

[3] Stewart, “8chan, Explained.”

[4] Mabunda, “Cryptocurrency.”

[5] Matsakis, Koebler, and Pearson, “This Twitter Bot Tracks Neo-Nazi Bitcoin Transactions.”

[6] Tracker, “New Payment to Henrik Palmgren (Http://RedIce.Tv ): 0.00519921 BTC ($20.16) Https://Blockchain.Info/Tx/127b726aa6ad4c43d41b1b6783d1a71e05c27deeae7a393b44ced91a032948a7 … Total of Henrik Palmgren (Http://RedIce.Tv ) BTC Wallets: 0 BTC ($0).”

[7] “Rise Above Movement.”

Friend of Foe?: An Analysis of Factors Influencing Sentence Length in the Prosecution of Terrorism

The posts below are brief summaries of 14-week research projects designed and carried out by our student team. tPP plans to release the full studies as peer-reviewed publications in the future.

Friend of Foe?: An Analysis of Factors Influencing Sentence Length in the Prosecution of Terrorism

Megan Burtis & Liz Butler

Our research project utilized a grounded theory case study analysis to determine which factors influence the extent to which the Federal Sentencing Guidelines are adhered to in the prosecution of terroristic cases.

The cases we analyzed we United States v. Burgert et al., United States v. Boyd et al., and United States v. Dibee et al. All findings within our paper were the result of the analysis of the three case studies we selected. Using a grounded theory approach, the analysis of these findings yielded the creation of specific categories which provide a theory as to what factors have the greatest impact on sentencing. Our paper theorizes that government manipulation of the Federal Sentencing Guidelines plays the biggest role in determining the final sentence length of defendants prosecuted for terroristic crimes. Thus, the way in which the government views a defendant ultimately determines their sentence.

Four key factors were found to influence the government’s view of defendants which include the plea entered by the defendant, the level of regret the defendant shows for the crime committed, the degree to which the defendant continues to support the ideology which motivated their crime, and finally the extent to which the defendant cooperated with the government during both the investigation and adjudication. The evaluation of these factors allowed for defendants to be placed in specific categories, as shown in the table, which reflect whether they will receive sentences at the lower or higher end of what was recommended.

Our research tentatively supported our initial hypothesis that race/ethnicity, citizenship status, and “othered” status would be influential factors, but we would require more evidence to make this claim with any degree of certainty. Finally, these findings have significant implications for future research, specifically pertaining to the use of terrorism enhancements and plea bargains. Further research is recommended to see whether both or neither of these strategies are suitable as a counterterrorism measure. Further research into the generalizability of our theory will also be required to test its applicability.

Deportation Station: How the United States Decides Who Stays and Who Goes

The posts below are brief summaries of 14-week research projects designed and carried out by our student team. tPP plans to release the full studies as peer-reviewed publications in the future.

Deportation Station: How the United States Decides Who Stays and Who Goes

Zoe Belford

My paper assessed what conditions lead to an increased likelihood of deportation following a guilty verdict in a United States terrorism prosecution, as well as if and how this relates to post-9/11 national security policy.  My sample included all cases in the Prosecution Project’s database that included a defendant with foreign citizenship, as well as had ended in a guilty verdict. This resulted in a sample size of 306, which I divided into two subsamples – cases which ended in deportation and cases which did not. Using these two samples,  I conducted a descriptive statistical analysis to find if any notable differences existed between the two groups.

My findings were as follows. Compared to non-deported defendants, deported defendants were:

    • Less likely to have a case involving a co-defendant
    • Less likely to have been charged with a previous similar crime
    • More likely to have completed the crime they were charged with
    • Less likely to have their case involve an informant
    • Less likely to be affiliated with a foreign terrorist organization
    • Have, on average, significantly lower sentence lengths
    • More likely to have an unclear ideological affiliation
    • Less likely to have an affiliation with a Salafi/Jihadist ideology
    • More likely to be Middle Eastern/North African

All of these findings hold the potential for further research, but I focused on the variable of foreign terrorist organization (FTO) affiliation. I found that deported defendants are known to be FTO-affiliated in only 35% of cases, whereas non-deported defendants are known to be FTO-affiliated in 72% of cases.

During my research for this project, I came across a theory that seemed particularly applicable to my observed findings. Based in economic and national security studies, mosaic theory posits that bits of intelligence can be pieced together by hostile parties (i.e. foreign intelligence agencies, foreign terrorist organizations) to form a picture of US intelligence practices and knowledge [1]. Since 9/11, this theory has played a significant role in the United States court system. Specifically, it was used to justify the classification of documents regarding the detainment of over seven-hundred people in regards to September 11th [2]. Based on my findings, I hypothesize that that the government is choosing to keep defendants who are more intertwined with known terrorist organizations within the country to avoid the potential intelligence risks of a deportation hearing. Deportation hearings can only be closed in a select number of circumstances [3], whereas the precedent to use mosaic theory to justify the classification of criminal proceedings has already been set.


[1] Neuman, Gerald L. 2005. “Discretionary Deportation.” Georgetown Immigration Law Journal 20: 611–56.

[2] Pozen, David E., James E. Baker, Jessica Bulman-Pozen, Fadi Hanna, Kenneth Levit, John Sims, and David Vladeck. 2005. “The Mosaic Theory, National Security, and the Freedom of Information Act.” Yale Law Journal.

[3] “Fact Sheet: Observing Immigration Court Hearings.” 2015. Department of Justice. February 10, 2015. https://www.justice.gov/eoir/observing-immigration-court-hearings.

USA Today cites tPP

We’re very proud to see that the amazing work of our student researchers was quoted today by USA Today in their article, “AOC says she gets death threats after organizations air ‘hateful messages’ about her”.

We hope to be a resource to media, policy makers, researchers and advocates in the years to come as our data set grows and improves!

Have a question we can answer, let us know?

How and Why Socio-Politically Motivated Crimes are Completed

The posts below are brief summaries of 14-week research projects designed and carried out by our student team. tPP plans to release the full studies as peer-reviewed publications in the future.

How and Why Socio-Politically Motivated Crimes are Completed

Tia Turner and Brenda Uriona

Brian Jackson, a senior physical scientist at the RAND Corporation, and David Frelinger, a senior policy analyst at RAND, constructed a report stating three main characteristics of what causes terrorist attacks to succeed or fail: terrorist group capabilities and resources, the requirements of the operation it attempted or is planning to attempt, and the relevance and reliability of security countermeasures. Utilizing the entirety of tPP dataset, we tested their theoretical framework on terrorism attacks using QCA complimented by frequency distributions and chi-squared analysis. With this, we expanded upon their framework by utilizing the dataset’s inclusivity of all socio-politically motivated crimes. We measured attacker group capabilities as a binary of the perpetrator’s group affiliation or lack thereof and measured operational complexity through the variable “Tactic,” redefined in terms of violence as a binary of “Yes”- violent or “No”- nonviolent. Crimes coded as violent are operationally defined to have greater complexity than nonviolent ones (see Figure 1 below).

We believe and assume completion of a crime will be significantly dependent on type of instigator and violent or nonviolent tactic. Additionally, we are adding upon the framework a more specific take onto instigator identity with tPP variable “‘Other’ Status.” If tests run on othering bring rise to a significant indication of whether or not a crime was completed, we plan to examine which trait characteristics are possibly targeted by security countermeasures, if any.

Altogether, these will reveal how and why socio-politically motivated crimes are completed and what can be done as time goes on. Work like this is essential because of its ability to show judicial bias. We believe if “Other” status is a significant indicator of crime completion it may be caused by Othering from counter securities and law enforcement’s implicit bias. Understanding indicators of why a crime is completed to at least some measure of success is critical for developing effective security measures. By testing all socio-politically motivated crimes, signs will prove to have greater generalizability that can help create more exhaustive and efficient consideration and efforts against crime.

In the end, both the QCA and exhaustive CHAID classification tree analysis (Figure 2) showed “Tactic” and “Group affiliation” to be significant indicators for “Completion of crime,” proving dependent correlation.

Overall, “Group Affiliation” proved to be the strongest indicator with a p-value of 0.00 at the 95% confidence level. Crimes committed by perpetrators with group affiliation are significantly more likely to succeed (61%) compared to perpetrators without group affiliation (39%). Analysis of “Tactic” at the 95% confidence level, p = 0.013, shows crimes utilizing a violent tactic, meaning one of greater operational complexity, are significantly less likely to be completed (55%) than crimes using a nonviolent tactic (45%). Alternatively, opposing our hypothesis, “‘Other’ status” is not indicative of crime success or failure. Future research could focus on more specific trait characteristics of the variables found significant through this study. Using what is commonly found in group capability and operational complexity within large datasets like tPP (e.g. pre-incident indicators) can ensure reliability and continue to aid in the establishment of more effective security countermeasures.



Brian A. Jackson, and David A. Frelinger. Understanding Why Terrorist Operations Succeed or Fail. Santa Monica, CA: RAND Corporation, 2009. https://www.rand.org/pubs/occasional_papers/OP257.html.

Loadenthal, Michael, et al. 2019. “The Prosecution Project (tPP)” (Version March 2019) [Dataset]. Miami University Sociology Department. https://tpp.lib.miamioh.edu.

tPP Preliminary Statistical Report #5 of 5

The following report was completed by statistics students utilizing a version of tPP dataset as of March 13, 2019. These analyses are focused on developing models for future use, and the interpretations and conclusions they contain reflect a dataset still in development, and only a superficial engagement with the wider literature on political violence. We continue to expand, improve and refine the data, and as such, these analyses should be seen as preliminary and subject to change. This views expressed in these reports belong solely to the authors, and do not necessarily reflect the findings of tPP team and are subject to further inquiry and revision.

Below you will find the non-technical and technical analytical summaries and selected visualizations for Team #5 (Classification & Characteristic Tree Analysis) of 5.

This report was authored by Brent Crist, Elena McDonald & Yuan Liu, Xinru YuTo download the complete report, including the statistical source code, click here.

Non-Technical Summary


Classification of terrorist attacks is the main problem of the Prosecution Project. Terrorism is one of the hottest topics in the news today, due to its increasing prevalence. Looking at acts of terrorism or political violence from a case-to-case basis, it is interesting to see how the government classifies each of them. Having the only reason for inclusion being “State Speech Act” in comparison to a combination of State Speech Act with other reasons, or no State Speech is of interest. Determining factors for why and how the government labels these cases provides an opportunity for analysis. The data comes from The Prosecution Project (tPP) from the sociology department at Miami University and yields the Reason for Inclusion, Tactic, Number Killed, Number Injured, and Othered Status for each case. This tPP dataset looks into the taxonomy of felony criminal cases involving illegal political violence, occurring in the United States since 1990. Utilizing the tPP dataset will allow for an explanation of the government classifications and the effects these variables have on the decision and how it changes through time.


The Lethality variable is split by Reason of Inclusion categories: State Speech (the motivation for the terrorist act is explicitly political), No State Speech (the motivation for the terrorist act does not involve political purposes), and Combination (a mixture of the two). For better examination of the distribution for the lethality, below is the mean and the standard deviation for each reason, along with the number of cases belonging to the Reasons. It is clear that mean and standard deviation of State Speech are the lowest and have a large variability in comparison to No State Speech and Combination. It also occurs in the same as number of cases.

Looking at the Methods attackers are using, the top three Methods per Reason for Inclusion are below. Providing Support to a terrorist organization is the top method for No State Speech and a Combination. Non-political Method is the most common for State Speech and represents over half of all State Speech Cases. Generally, terrorist attacks in the news, in recent years, involve explosives, firearms, and/or vehicle ramming. The Explosives Method appears less frequently than one might expect, given the frequency of news articles.

The third variable of interest is Othered Status. The table below, once again, breaks down Othered Status into each Reason for Inclusion. For both State Speech and a Combination, Othered individuals heavily out number Non-Othered. In cases that are No State Speech, the two groups are almost perfectly split fifty-fifty.


For Lethality, no state speech is the most common reason, where state speech is much lower. Interestingly, providing support to terrorists or terrorist organizations is the most frequently encountered category for both no state speech and combination. Given the size of both of these categories, the frequency of this providing support is of interest to researchers for its implications in both separate categories. In all cases, the othered status of an individual might help researchers better understand how the state labels these people as terrorists. Because the categories state speech and combination carry implications of a directed attack against the state, the juxtaposition of the othered status reveals data to researchers who might be studying the othered status of terrorists.

Technical Summary


The Prosecution Project provides a chance to determine when and what factors cause the state to label a criminal act as terrorism. In this analysis, many different techniques aid the process of determination of how these acts make the list. Data manipulation and cleaning assist the analysis by creating convenient (and statistically viable) groupings. Summary statistics and data visualization further enhances the ability to better understand how these variables change over time and how they relate to one another. Creating a characteristic tree is a strong method for analyzing what factors cause the government to label criminal acts as terrorism. The random forest method allows for validation of pruned trees and aids the analysis in this paper.


Data cleaning and manipulation are the first two crucial steps to proper analysis. For the tPP data, the research question revolves around the following variables: Reason for Inclusion, Tactic, Lethality, Other Status, and Date. Lethality is not a variable present in the data set; construction of the Lethality variable consists of adding the total kills and injuries per case, resulting from an offense. To answer the time element to the research question, the use of presidential terms creates meaningful time intervals for comparison. Associating the Day, Month, and Year of an event with the Day, Month, and Year of the inauguration of each president (in the scope of the data frame) allows for this timeline to form. The earliest case in the data frame occurs during Bill Clinton’s service, while the latest case occurs during Donald Trump’s service, with George W. Bush and Barack Obama in between. By adding the political affiliation of each president, another layer of analysis and comparison comes into play.

For purposes of the characteristic tree analysis, reduction of the Tactic variable with twenty unique levels is necessary. Reducing the number of levels gives more splitting power in the characteristic trees, further in the analysis. The percentage of cases involving each tactic hints at how much information each unique tactic provides to the overall analysis. Having eight levels, seven without Other, rather than the original twenty levels strengthens the resulting analysis.

Reason for Inclusion also must undergo manipulation. To look specifically at the prevelane of the State Speech Act, splitting of Reason for Inclusion reflects this act. The three groups become cases that are State Speech, Not State Speech, and a Combination of the State Speech Act and other reasons. With this new variable, along with the others, the data are ready for investigation. Working with the data, summary statistics for Reason, Method, Lethality, and Other Status show how the data behaves and what it looks like. Additionally, separating bar graphs for the same set of variables by President, shows how each of these are changing in time. The bar graphs for Reason, Method, and Other Status are proportions while the bar graph for Lethality represents a count.

Creation of a characteristic tree (Buntine, 1992) can help analyze what factors cause the government to include each case, and the reason for the inclusion. Building a characteristic tree is not enough, both cross-validation and building a random forest provide insight as to how well the tree fits to the data. Execution of this technique in R, by partitioning the data into a training and testing set, produces this information. Fitting a tree, using a cost element for each partition, creates the optimal tree which will undergo methods of cross-validation (Zhong, 2016).

Comparing the values of the predictions and the real data computes the accuracy of these models. Further testing of the accuracy comes from the Random Forest, in the creation of a large sample of random trees (Zhong, 2016). By creating a large number of random trees, which use a random selection of the variables to split on, provides more evidence of model accuracy. The random forest generalizes the process, as such, the comparing predictions from the testing data set gives a stronger accuracy measure.

Many R packages are essential for the methods of this analysis. These procedures require the lubridate (Grolemund and Wickham, 2011), caret (Kuhn and Others, 2019), rpart (Therneau and Atkinson, 2018), rpart.plot (Milborrow, 2018), and randomForest (Liaw and Wiener, 2002) packages in R.


In order to properly understand the motive of terrorist attacks, the execution methods play a vital role in their inclusion to this dataset. The Prosecution Project includes an exhaustive list of methods detailing how the acts are committed; however, grouping methods with similar tactics allow for proper analysis. That is, all acts, including acts that effectively serve as the threat of committing another act, are in the same group for analysis (e.g. “Explosives” and “Bomb Threats” become “Explosives”). Additionally, tactics that are “Unspecified” are not useful to a deeper understanding and hence, do not appear in this analysis. Lastly, all tactics that comprise less than 1% of the total tactics and do not fit neatly into the aforementioned methods (Animal Release, Blockading, Unarmed Assault, Vandalism) do not appear in this analysis (see Prevalence of Tactic table in Appendix for more details). These categories, with the terrorists’ reasoning, offer more insight into how a terrorist attack carries out given their motivation. The table below shows the prevalence of each Method in the data in relation to each Reason for Inclusion.

Interestingly, more than half the cases that are State Speech are Non-Political (e.g. James Tyler Williams who killed a homosexual couple because they were gay). The majority of State Speech cases are Non-Political which are non-violent crimes relating to assisting terrorism or denying the ability of the state to pursue these crimes. No State Speech’s top three methods together account for 62.2% of the cases in this category. This means that there is a higher spread of types of crimes as opposed to State Speech’s Non-Political or Combination’s Provide Support which are more highly skewed to these crimes.

The summary statistics of lethality per method provides useful insight into how each of these crimes change by lethality. For instance, the mean lethality of Firearms should be different from the Provide Support method. The standard deviation also shows the spread of each of these methods.

Most cases yield results that fit the narrative of terrorism. Notice the higher means in the Firearms and Hostage/Standoff categories and the lower means in Non-Political and Provide Support categories. Higher standard deviations in the Explosives, Firearms, and Hostage/Standoff categories create a level of uncertainty in how many people are likely to be killed or injured from one of these attacks.

The Othered Status of an individual provides notable statistics for the Reason for Inclusion as well. It is critical to note that the Othered Status itself is quite subjective and is not a uniform label. That is, in no way are there exact criteria for a terrorist to be given an Othered Status. Mapping the Othered Status of a person to the reason their crime was included in the database allows for insight on how an othered person’s crime might be perceived by the State.

State Speech has the largest discrepancy between Othered and Non-Othered Status. This is to say that the vast majority of terroristic acts, when involving State Speech, are by Othered people. Whether or not this has any bearing to what period of time these acts happen appears later in this paper. No State Speech sees an almost even percentages by either Othered or Non-Othered people. As the guidelines for No State Speech are less specific than the other Reasons for Inclusion, there might be less cause for people of Othered and Non-Othered status to commit motivated terrorist attacks and more for the sake of senseless violence. The Combination Reason for Inclusion sees just over twice as many Othered people committing terrorist attacks for this reason as Non-Othered people.

As technology and geopolitical climates change with time, so too does the methodology of a terroristic act. Grouping these methods by their place in time relative to the President in office at the time of their happening gives way to visual representation of these statistics.

Drastic changes come over the years as the geopolitical climate changes. Notice there is a massive increase in the Provide Support (yellow) Method in the Bush, Obama, and Trump Administrations vice the Clinton Administration. This could be due largely to the fact that the Global War on Terror takes place during these Presidencies but not during Clinton’s. It is not unreasonable to believe that the United States, as a strategy to deter violent terrorism, is labeling more non-violent crimes as terrorism than in years past. Since the United States is an economic superpower, its dollar has more buying power around the world. Because of this, terrorist sympathizers are able to accrue cash with much more buying power than in their home countries (assuming they support foreign terrorist organizations). This results in the ability of foreign terrorist organizations to acquire much higher numbers of supplies for violent terrorist attacks.

As the changing of methods through time offers insight into how the United States labels a crime as a terroristic act, the Othered Status of a person, too, changes in time. Different conditions in the United States during the four Presidencies included in this dataset might offer clues into how the status changes.

Notice, again, how the Othered status of terrorists changes drastically after the Clinton era. The United States, during this time period, could be experiencing higher sensitivity to terrorism due greatly to the loss of life from the September 11 attacks. As the Global War on Terror continues through the years, the Othered status of terrorists lowers. Whether this is due to a Liberal Obama Administration and a smaller sample size for the Trump Administration or that the United States and its citizens are becoming less skeptical of the people committing these crimes requires further study.

Seeing how the lethality of each of these acts changes in time can give clues as to how violent the crimes committed in these separate time periods are. Given the rise in non-violent methods in the past three Presidencies, studying the counts of lethality in their terms will shed light on how many people were killed in violent terrorist attacks in these time periods.

The lethality of these attacks again increases substantially during the years following the September 11 attacks. It is important to note that President Donald Trump has only been in office for just over two years at the time of conducting this analysis. The significantly lower lethality could be due mostly to the fact that the sample size is much smaller.

Seeing how the Method, Othered Status, and Lethality has changed through time then lends itself to studying how all terroristic acts included in the dataset has changed. Political moods and outside factors might play into how these crimes are included, and can be visualized by plotting them by the four Presidencies included in tPP.

A large change in No State Speech occurs from the Clinton to Bush Administrations. It is difficult to determine whether this is due to the United States’ sentiment towards terrorism changing after the September 11 attacks or some other unknown variable. The Combination and State Speech groups constitute the largest change from the Clinton to Bush Administration. From the Bush to Obama Administration, a change in these two categories again occurs with State Speech becoming less prevalent and Combination becoming more prevalent. The increase in the Combination group might be a result of President Barack Obama being the first African American President in the history of the United States. A terroristic act due to this fact along with other racially charged motivations constitutes inclusion in the Combination group; however, this hypothesis requires further analysis and is not part of this study.

Machine learning processes can help to classify each case, with respect to their Reason for Inclusion, by the separate variables in the dataset. Splitting each of the nodes into various methods, Presidents, and lethality allows for the computer to decide where a case might fit based on the given factors and to create a Classification Tree from these splits.

The most important factor in this tree is the Method. From the first partition, all of the methods are present except for Non-Political and Perjury/Obstruction of Justice, which lends itself to the State Speech node on the right. The only Methods for which a case is likely to be State Speech are Perjury/Obstruction of Justice or Non-Political. Of note, President is the second partition on both the No State Speech and the State Speech nodes and that Obama appears in both of the positive splits for president. Only 10% of the entries fall under the criteria of Non-Political Method. Additionally, there is no partition that requires the Othered Status or Lethality in this tree. This tree shows a path of which to follow to see the categorization by the government of each type of case. The model accuracy rate of this optimized tree is about 65%, this comes from comparing the predicted values with those in the testing data set. A confusion matrix allows for the analysis of the performance of a Classification Tree. The model is the most accurate in predicting cases of State Speech and the least accurate for cases of a Combination.

The above procedure of obtaining a pruned tree involves using a training and testing data set. Splitting the data and training a model on part of it and then testing the model on the other part is a form of cross-validation. Another way to check the accuracy of the model is through a random forest. A random forest allows for validation of singular trees. Random forest importance plots show the validity of five hundred random trees from the data.

The Mean Decrease Accuracy and Mean Decrease Gini coefficients plots how important a variables is to the partitioning process in the creation of a characteristic tree. The further along a variable is on the x-axis (in both plots) signifies a greater presence in the partitioning process in randomly generated trees in the forest. As in the earlier singular characteristic tree, Method again is the most important variable for determining whether an act is State Speech, No State Speech, or Combination. Despite the large gaps in the variables (meaning the partitioning process becomes less accurate), it is worth noting that the variables in this order help to increase the validity of the singular tree. Lethality and Othered Status are the two least important predictors, according to the random forest data. Summarily, this means that the order of importance for determining the Reason for Inclusion is Method, President, Lethality, and Othered Status. The accuracy rate for the random forest is 70.2%, meaning the model for this data is predicting cases correctly 70.2% of the time.


Many outside political factors (e.g. the September 11 attacks, the Global War on Terror, Presidential Administration) can affect how the government classifies crimes as terroristic acts or not. These classifications do change over time and the involving methods play a significant role in determining whether they are state speech acts of terrorism, not affiliated with state speech, or a combination of the two. In predicting what a government will classify a case as, the method by which a crime is committed and the President in office at the time of its being committed, in order of importance, have the most impact. The others do not provides as much information, but they are, in order of relevance, lethality of the crime and the Othered Status of the terrorist committing the crime. The splitting power of President in the characteristic trees drives home the finding of how the Reason for Inclusion changes in time. The random forest solidifies the importance of the variables presented in the pruned tree through the Mean Decrease Accuracy and the Mean Decrease Gini. Not surprisingly, the pruned tree ended with five terminal nodes, two of which were No State Speech, two of which were Combination, and only one was State Speech. These results are consistent with the raw counts of each of the individual reasons for inclusion. With a 65% accuracy rate in the pruned tree and a 70% accuracy rate in the random forest, there is reason to believe that the variables in these trees make for important determining factors in whether a terroristic act will be classified as a state speech act, a non-state speech act, or a combination of the two.