Business books and management gurus have long sung the praises of giving employees free time to tinker on projects they initiate. The idea seems to have begun with 3M, who allowed employees to spend 15 percent for their workweek focused on projects that were unrelated to their normal work. More recently, Google upped the percentage to 20 percent of the workweek. Many other tech companies seem to have followed suit, some changing the formula a bit to establish dedicated “hack weeks” or “FedEx days” where all employees shed their normal projects and tinker with ideas that are inherently interesting to them. For companies that use such programs, innovation seems to increase. 3M points to legendary products such as the Post-It note as proof of its effectiveness. Google can hold up Gmail, Google News and AdSense as vital products birthed in 20 percent time.

The programs work. But why?

Despite their public successes, few efforts have been made to study these programs and uncover the reasoning behind why they work. To that end, my friend and co-author Gary Oster and I have recently published a paper exploring just that. Our paper explores what we call “Noncommissioned Work” (a term borrowed from Daniel Pink) and attempts to offer an explanation for why such programs yield innovative ideas.

We offer three propositions:

Noncommissioned work offers autonomy. Evidence indicates that employees are more motivated to work on projects and more creative in their work when they’re given freedom to set their schedule and structure their tasks. During periods of noncommissioned work, individuals are free to do just that.

Noncommissioned work reduces incentive salience. While a final conclusion is up for debate, there is a strong line of research supporting the concept that extrinsic rewards such as bonuses and prizes actually decrease the creativity of the intended individual. During periods of noncommissioned work, incentive compensation becomes an afterthought since the project at hand isn’t sanctioned by the organization (at least not yet).

Noncommissioned work increases risk-taking. At its heart, innovation requires risk-taking. Studies of employees in R&D labs reveal that those with more willingness to take risks experience greater creative gains. Periods of noncommissioned work offer a safe environment for risk-taking by employees that frees them to fully exercise their creativity.

Noncommissioned work appears to be a viable option for many leaders looking to enhance the creativity of their people without making large-scale changes to their organizations. They can begin experimenting with what we label “transient noncommissioned work,” offering employees a certain day or week on the calendar to tinker and be creative. If these experiments prove fruitful, they can consider expanding to “persistent noncommissioned work,” where employees have freedom over a portion of their calendar.

Noncommissioned work programs work. Perhaps now we know why.