When the hunt is on for causes of lost productivity, there’s a long list of usual suspects. Bad traffic and long commutes, problems at home, poor management, and even company culture. Office illumination may seem spurious by comparison, but plenty of studies suggest that it’s not only a key problem, but it’s an ongoing one.

In the 1980s, a report commissioned by the American Society of Interior Designers found that 68% of office workers were not satisfied by the lighting in their workplace. In the early 2000s another study, undertaken by Cornell University, found that 24% of office workers blamed lighting for productivity dips due to eyestrain and discomfort.