The authors reanalyzed data from 2 influential studies-A. R. McConnell and J. M. Leibold (2001) and J. C. Ziegert and P. J. Hanges (2005)-that explore links between implicit bias and discriminatory behavior and that have been invoked to support strong claims about the predictive validity of the Implicit Association Test. In both of these studies, the inclusion of race Implicit Association Test scores in regression models reduced prediction errors by only tiny amounts, and Implicit Association Test scores did not permit prediction of individual-level behaviors. Furthermore, the results were not robust when the impact of rater reliability, statistical specifications, and/or outliers were taken into account, and reanalysis of A. R. McConnell & J. M. Leibold (2001) revealed a pattern of behavior consistent with a pro-Black behavioral bias, rather than the anti-Black bias suggested in the original study.Keywords: Implicit Association Test, predictive validity, discrimination, implicit biasThe Implicit Association Test (IAT; Greenwald, McGhee & Schwartz, 1998) has become one of psychology's most popular exports to the wider social sciences and the law (e.g., Lane, Kang, & Banaji, 2007). The measure's popularity is easy to grasp: IAT researchers often inform test takers they harbor implicit or unconscious biases toward minorities that many test takers disavow at a conscious level (Dasgupta, Greenwald, & Banaji, 2003). According to the much-visited Project Implicit Web site, without constant vigilance these implicit biases may lead to unwanted behaviors:People who hold egalitarian conscious attitudes in the face of automatic White preferences may [be] able to function in nonprejudiced fashion partly by making active efforts to prevent their automatic White preference from producing discriminatory behavior. However, when they relax these active efforts, these nonprejudiced people may be likely to show discrimination in thought or behavior. (IAT Corporation, n.d., Question 16) It is this claimed connection between implicit attitudes and discrimination that can make IAT feedback particularly disturbing to test takers. It also is the feature that makes research on the IAT of broad interdisciplinary interest. If the race IAT reliably predicts discriminatory behavior that cannot be consciously controlled, then society should take note. As but one example, the great majority of White Americans who have taken the IAT have been classified as anti-Black. This then points to an epidemic, either of unconscious racism (Greenwald & Krieger, 2006) or of falsepositive accusations of unconscious racism (Mitchell & Tetlock, 2006).Given the importance of the link between IAT scores and behavior, one might expect to find a large body of data establishing this connection-indeed, Greenwald and Krieger (2006, p. 961) described the evidence that implicit bias leads to discriminatory behavior as "already substantial." In fact, researchers in only a few studies have examined the ability of the IAT to predict behavior of any type, and resear...

Changes in the terror alert level set by the Department of Homeland Security provide a shock to police presence in Washington, D.C. Using daily crime data during the period the terror alert system has been in place, we show that the level of crime decreases significantly, both statistically and economically, in Washington, D.C., during high-alert periods. The decrease in the level of crime is especially large in the National Mall. This provides strong evidence of the causal effect of police on the level of crime and suggests a research strategy that can be used in other cities.

If medical malpractice reform affects the supply of physicians, the effects will be concentrated in specialties facing high liability exposure. Many doctors are likely to be indifferent regarding reform, because their likelihood of being sued is low. This difference can be exploited to isolate the causal effect of medical malpractice reform on the supply of doctors in high-risk specialties, by using doctors in low-risk specialties as a contemporaneous within-state control group. Using this triple-differences design to control for unobserved effects that correlate with the passage of medical malpractice reform, we show that only caps on noneconomic damages have a statistically significant effect on the per capita number of doctors and that this effect is concentrated among only those specialties that face the highest litigation exposure.

Changes in the terror alert level set by the Department of Homeland Security provide a shock to police presence in Washington, D.C. Using daily crime data during the period the terror alert system has been in place, we show that the level of crime decreases significantly, both statistically and economically, in Washington, D.C., during high-alert periods. The decrease in the level of crime is especially large in the National Mall. This provides strong evidence of the causal effect of police on the level of crime and suggests a research strategy that can be used in other cities.