Organized intergroup violence is almost universally modeled as a calculated act motivated by economic factors. In contrast, it is generally assumed that non-economic factors, such as an individual’s emotional state, play a role in many types of interpersonal violence, such as crimes of passion. We ask whether non-economic factors can also explain the well-established relationship between temperature and violence in a unique context where intergroup killings by drug-trafficking organizations (DTOs) and other interpersonal homicides are separately documented. A constellation of evidence, including the limited influence of a cash transfer program as well as comparisons with both other DTO crime and suicides, indicate that economic factors only partially mitigate the relationship between temperature and violence that we estimate in Mexico. We argue that non-economic psychological and physiological factors that are affected by temperature, modeled here as a “taste for violence,” likely play an important role in causing both interpersonal and intergroup violence.
This study estimates the effect of data sharing on the citations of academic articles, using journal policies as a natural experiment. We begin by examining 17 high-impact journals that have adopted the requirement that data from published articles be publicly posted. We match these 17 journals to 13 journals without policy changes and find that empirical articles published just before their change in editorial policy have citation rates with no statistically significant difference from those published shortly after the shift. We then ask whether this null result stems from poor compliance with data sharing policies, and use the data sharing policy changes as instrumental variables to examine more closely two leading journals in economics and political science with relatively strong enforcement of new data policies. We find that articles that make their data available receive 97 additional citations (estimate standard error of 34). We conclude that: a) authors who share data may be rewarded eventually with additional scholarly citations, and b) data-posting policies alone do not increase the impact of articles published in a journal unless those policies are enforced.