SHOCKER: To improve diversity, don’t make people go to diversity training. Really.

Companies have tried everything to boost the stubbornly anemic numbers of women and minorities in management roles or in certain industries, such as tech or finance. They’re making candidates’ resumes blind to race and gender. Setting up partnerships with historically black colleges. Releasing demographic data in an exercise of public accountability — and humility.

But perhaps the most common and seemingly elementary tactic — compulsory diversity training aimed at helping people’s biases or preventing discriminatory behavior — appears to actually do more harm than good.

In the cover story of the latest issue of the Harvard Business Review, sociologists from Harvard University and Tel Aviv University explore the counterintuitive idea that some of the most common tools for improving diversity — one of which is mandatory training — are not just ineffective. They could be detrimental to improving the number of women and minorities in the managerial ranks.

Making people attend diversity training may seem to make sense, said one of the study’s co-authors, Alexandra Kalev, in an interview: “But it doesn’t work. For decades, diversity management programs flourished with no evidence whatsoever about their effects and their success.”

They enrich consultants and let managers pretend they’re doing something.