These figures suggest the possibility that the Brady act might be effective in screening prohibited purchasers from making gun purchases from FFLs. Based on descriptive studies revealing heightened risks of subsequent gun offending, some researchers suggest extending the provisions of the Brady act to a wider range of at-risk individuals, such as persons with prior felony arrests (Wright et al., 1999) and misdemeanor convictions (Wintemute et al., 1998). Wright et al. (1999) compared the gun arrest rates of two groups in California. The first consisted of persons who were denied purchases because they had been convicted of a felony in 1977. The second was purchasers who had a prior felony arrest in 1977 but no conviction. Even though the former group would reasonably be labeled as higher risk, they showed lower arrest rates over the three years following purchase or attempt to purchase. It is important to recognize that the group of convicted felons who attempt to purchase through legal channels may be systematically lower risk than the entire felony population, precisely because they did attempt to use the prohibited legitimate market; the finding is suggestive rather than conclusive
Wintemute et al. (1998) also recognize that extending the provisions of the Brady act would greatly complicate the screening process. Moreover, while this policy seems to prevent prohibited persons from making gun purchases in the primary market, the question remains what, if any, effect it has on purchases in the secondary market, on gun crimes, and on suicide.
Using a differences-in-differences research design and multivariate statistics to control for state and year effects, population age, race, poverty and income levels, urban residence, and alcohol consumption, Ludwig and Cook (2000) compared firearm homicide and suicide rates and the proportion of homicides and suicides resulting from firearms in the 32 states affected by Brady act requirements (the treatment group) compared with the 19 states and the District of Columbia (the control group) that had equivalent legislation already in place. Ludwig and Cook (2000) found no significant differences in homicide and suicide rates between the treatment and control groups, although they did find a reduction in gun suicides among persons age 55 and older in the treatment states. This reduction was greater in the treatment states that had instituted both waiting periods and background checks relative to treatment states that only changed background check requirements. The authors suggest that the effectiveness of the Brady act in reducing homicides and most suicides was undermined by prohibited purchasers shifting from the primary market to the largely unregulated secondary market.
While the Brady act had no direct effect on homicide rates, it is possible that it had an indirect effect, by reducing interstate gun trafficking and hence gun violence in the control states that already had similar laws. Cook and Braga (2001) document the fact that criminals in Chicago (a