Economists have always been wary of aging populations, particularly because an increase in retirees can lead to a smaller labor force, essentially hurting economic growth. But new research has identified a more powerful impact.

A study from Harvard University concludes that an increase in the aging population is depriving companies of access to workers with the experience and knowledge needed to keep their businesses running smoothly, the Wall Street Journal reports. The study tracked the economic growth of 50 states—because each state's population ages at a different pace—and found that for every 10% of a state's population that turned 60 and up, the GDF fell by 5.5% per capita.

But only one-third of that drop stemmed from a smaller labor force, the other two-thirds came from the effects of less experience in the workplace—suggesting that productivity suffers when experienced employees retire. [WSJ]