Executives acknowledge that playing favorites runs rampant in the workplace. But good luck getting individual executives to admitting that they engage in the practice.

This unwritten rule of the workplace surfaced in a study by a researcher at Georgetown University's McDonough School of Business.

Jonathan Gardner, an executive himself (at research firm Penn Schoen Berland), wanted to get some idea of how widespread the practice of playing favorites was, and also whether participants in his study would fess up to do it themselves.

• 92 percent said they have seen favoritism at play in employee promotions;

• 84 percent said it happens where they work;

• 23 percent owned up to playing favorites themselves;

• 9 percent said they have used favoritism in their last promotion decision;

• 56 percent said that, in promotion situations involving more than one candidate, they knew ahead of the interviews which one they wanted to promote. Of those, 96 percent promoted the favorite.

.Yet rather than embracing and celebrating favoritism for the good feelings generated between beaming boss and fawning favorite, companies continue to attempt to stamp it out.