Often, it’s the workers themselves who are reluctant to skip the drive into work.

Almost half (46%) of workers said their companies allow them to work from home — but only 32% actually do it, according to a recent survey by Steelcase, Inc. Why?

One biggie: They don’t think it’s a smart career move. Of the workers who can telecommute but don’t, 71% said they think their bosses would worry about a drop in productivity and 64% thought they’d be skipped over for a promotion if they weren’t in the office every day.

They might be on to something: Half the respondents overall said they are in fact more productive in an office environment.

That’s a key bit of info for managers to note. As more employers offer the arrangement, it’s going to be important for managers to keep an eye on who’s getting the work done and who isn’t.