With the happiness questionnaire, how is the overall happiness of the employees of the companies calculated, just a straight up average? So if the company made sure the really shitty stuff was compartmentalized to a very small portion of the employees, then they would be rewarded? If it’s determined by the least happy employees, a company could fire the least happy employees and be rewarded.

Send the questionaire to anyone who gets a w2 from that company. Set multiple factors to determine over all taxes paid. A good average could reduce your taxes by x%, but too many very unhappy outliers could raise it back up by even more.