Many other researchers have come to opposite conclusions. John Donohue, an economist at Stanford University, reported in a working paper in June 2017 that when states ease permit requirements, most violent crime rates increase and keep getting worse. A decade after laws relax, violent crime rates are 13 to 15 percent higher than they were before. And in 2004 the National Research Council, which provides independent advice on scientific issues, turned its attention to firearm research, including Lott's findings. It asked 15 scholars to reanalyze Lott's data because “there was such a conflict in the field about the findings,” recalls panel chair and criminologist Charles Wellford, now a professor emeritus at the University of Maryland. Lott's models, they found, could be tweaked in tiny ways to produce big changes in results. “The analyses that we did, and that others have done, show that these estimates are very fragile,” Wellford explains. “The committee, with one exception, concluded that you could not accept his conclusion that more guns meant less crime.” Wintemute summarized it this way: “There are a few studies that suggest that liberalizing access to concealed firearms has, on balance, beneficial effects. There are a far larger number of studies that suggest that it has, on balance, detrimental effects.”