Despite the benefits flexible work schedules offer— among them greater productivity, efficiency, and satisfaction among employees—long-held perceptions of what a workday should be hold fast at many companies.

A recent study conducted by sociologists at the Sloan Center on Aging and Work at Boston College found that just one-fifth of companies offer flexible options to most of their employees.

One issue: Employees who take advantage of flexible schedules are not always treated the same as those who follow a more traditional work schedule.

For example, Quartz reports on a new study from The University of Washington that found managers perceive employees who start their days early as more disciplined, regardless of other performance indicators or how late in the evening the employee worked.

No matter how well flextime works, then, reaping its benefits requires a shift in organizational culture.