A new study suggests that unpredictable, inconsistent work schedules—a widespread source of frustration and hardship for people working service jobs, for instance in retail—may not even be what’s best for business.

The New York Times reports on a study conducted by researchers with the company’s cooperation at more than two dozen Gap stores:

The study randomly assigned about two-thirds of the stores to a so-called treatment group, in which managers were encouraged to provide workers with more consistent start and stop times from day to day, and more consistent schedules from week to week. Many managers were also authorized to slightly increase the total number of payroll hours that they could allocate to their workers. Scheduling at the remaining one-third of the stores continued largely as usual.

Surprise, surprise: Average sales increased seven percent.

The researchers say that in fact, overall shift consistency didn’t even increase that dramatically. What they theorize happened is that managers given more leeway focused most heavily on experienced workers, reducing turnover among the people with the best sense of what’s actually going on. And you’re more likely to stick around and actually purchase stuff when there’s somebody who knows the merch to answer your damn questions in a timely manner. Also, you’re likely better able to focus on recommending a hat to go with that particular sweater if you aren’t worrying about whether you’re going to make rent that month.

Which, in turn, suggests that it would be wise to invest in employees by treating them well, rather than as powerless cogs that you’ve got cornered. Read about the study in more detail at the New York Times.