A new study published in the Harvard Business Review by Tel Aviv University and Harvard University researchers finds that despite millions of dollars spent to settle discrimination lawsuits over the past two decades, women and minorities have not gained much ground in management in that time period.

Organizations are trying to reduce bias using the same kinds of programs they have been using since the 1960s. But these programs — diversity training, hiring tests, performance ratings, grievance systems — have tended to make things worse, according to the new study by Dr. Alexandra Kalev of TAU’s Faculty of Social Sciences and Prof. Frank Dobbin of Harvard University.

The authors’ analysis of data from 829 firms over three decades shows that these tools decrease the proportion of women and minorities in management. They’re designed to preempt lawsuits by policing managers’ decisions and actions. But as the lab studies show, this kind of force-feeding managers can activate bias and encourage rebellion.

“Decades of social science research point to a simple truth: You won’t get managers on board by blaming and shaming them with rules and re-education,” the researchers say. Instead, “a number of companies have gotten consistently positive results with tactics that don’t focus on control. They apply three basic principles: engage managers in solving the problem, expose them to people from different groups and encourage social accountability for change.”

For more, read the article in the Harvard Business Review.