Field of Research

Criminology, Urban Sociology, Social Inequality

Research Topics

(i) Understanding the effects of social policies and law enforcement on crime

(ii) Understanding the effects of crime-related events in shaping social inequality

Overview of Research 

My research focuses on communities and crime. In particular, I study (i) the conditions under which institutional contexts – both social policies and law enforcement – affect crime, and (ii) how crime-related events shape the persistence of community relations and social inequality. I exploit quasi-experimental research designs to examine these interrelated research questions. In the following paragraphs, I briefly summarize some of my research projects that speak to RQs (1) and (2).

RQ (1)

Medical Marijuana Laws reduce violence associated with Mexican drug trafficking organizations (joint with Evelina Gavrilova and Floris Zoutman)

Billions of dollars are spent to combat Mexican drug trafficking organizations, who play a crucial role in smuggling drugs to the U.S. and resort to violence for their revenues. This project considers an alternative way to combat Mexican drug trafficking organizations by examining the effect of medical marijuana laws on violence in the U.S.-Mexico border states. The graph below shows that the effect of medical marijuana laws on violence diminishes as counties in the U.S. are farther located from the U.S.-Mexico border.

Yakuza Exclusion Ordinances reduces the number of yakuza members but increases fraud (joint with Tetsuya Hoshino)

Unlike other countries, it is not illegal to form a criminal organized syndicate, the yakuza, or join one in Japan. Yet, Japan has recently tightened enforcement on them by enacting yakuza exclusion ordinances. This project studies the intended and unintended consequences of the ordinances. The graph below shows that the revenues of fraud increases as a response to the enactment of the yakuza exclusion ordinances.

RQ (2)

The crack epidemic in the mid-1980s has changed the residential landscape over two decades (dissertation)

Many U.S. inner-cities experienced the crack epidemic in the mid-1980s—an unusually violent and racialized drug epidemic. This project considers the long-run effects of the crack epidemic in the mid-1980s on the residential landscape over two decades by examining suburbanization, residential racial segregation, and neighbourhood concentrated poverty. The graph below shows that crack’s emergence increased black concentrated poverty in the inner-city over two decades.

Message to Students

Crime, urban problems, and social inequality are necessarily interdisciplinary. OSIPP comprises of researchers with various backgrounds. In this unique environment, I hope you are attentive to different perspectives and flexible with research ideas. My door is always open.

KAMADA, Takuma 
Associate Professor
Degree: Ph.D. in Sociology (The Pennsylvania State University)
kamada@osipp.osaka-u.ac.jp