A state bar-commissioned study concludes that California law school students’ undergraduate credentials and law school performance accounted for up to 50 percent of the decline in bar exam scores and passing rates between 2013 and 2017.

But much of the slump in pass rates on the July tests during that four-year period cannot be accounted for even after culling data from 11 participating American Bar Association-approved law schools, according to the report, dated Dec. 20 and conducted by Research Solutions Group.