NEW YORK (CNN/Money) - It goes against conventional wisdom but a new study suggests that companies looking to downsize can reap faster and better results if they take cull the herd from the bottom-up instead of from the top down, according to a published report Monday.

A report in USA Today said the new research recommends firing the bottom 10 percent of the workforce to improve company performance.

But there's a caveat: The "controversial" practice should be considered after three or four years because dead wood can only be removed once, according to the study published in Personnel Psychology. After that, the new hires are less likely to be any better than workers who are let go.

The paper, citing Workforce magazine, said one in five companies use some version of forced rankings, also known as "rank and yank" that require managers to go beyond evaluating workers and to rank them from top to bottom. But putting workers in the bottom 10 percent isn't easy if everyone is doing acceptable work.

"It's probably the most controversial issue in management today," the paper quoted Dick Grote, a consultant and author of the book Forced Rankings.

The lead author of the new research, Steve Scullen, said he stops short of recommending rank and yank because his study does not take into account intangibles such as morale, workplace cooperation, turnover and lawsuits, the paper said.

Microsoft is among those companies that do rank employees, the paper said, but the software maker clarified that the ranking is not to fire bad performers but to give promotions and bonuses.