You thought you left homework assignments behind when you graduated school? Think again. Employers continue to ask job candidates to complete take-home assignments, some of which are quite long and intensive. Companies often sell this “homework” as good for the candidates. After all, you can work on the questions at your own pace, in your own workspace, and use whatever tools or references you want. You can almost hear the hiring managers saying: “Well, tech pros complain that whiteboard interviews don’t let them consult Google or Github. Letting them take the work home is so much better for everyone!” But take-home assignments come with some pretty big caveats. Some employers’ problem sets are so long, completing them feels like a full-time job unto itself. On a more insidious level, unscrupulous companies have used these assignments as a way to get candidates to do real, impactful work for free. Even if you’re okay with doing homework, watch for these red flags:

Homework Comes First

In an ideal world, a prospective employer would only give you an intensive homework assignment once you passed at least one or two interviews; it’s a finer tool for deducing your skills, not a way to prune as many initial applicants as possible. If an employer wants you to complete a lengthy test before you speak to someone on the phone or come in for an interview, be cautious. (And yes, some companies give very short tests at the very outset of the application process, in order to make sure the applicant knows what code actually is; that’s different from the multi-question tests we’re discussing here, which are generally longer and meant to deduce the fineness of your sit for the position.)

Unclear Expectations

The company should make very clear what it wants out of a homework assignment. Telling you to solve a clearly defined problem set (five math questions, let’s say) or offer up a small programming snippet is one thing; telling you to “create a marketing plan” or “build a program that does X” with no clear idea of scope is quite another. In a similar vein, the homework should also come with a hard time limit. If the company seems willing to drag the assignment out—and keeps trying to add more work onto what you were initially assigned—that’s a big sign that something is wrong. A test that takes a couple hours might be fine, but one that stretches over a few days is not.

You’re Clearly Doing the Company’s Work

Employers stealing candidates’ job-application materials and other intellectual property is a long-running issue, and not just limited to tech. (In a Wall Street Journal column several years ago, Joann S. Lublin had an interesting solution to this sort of thing: complete the assignment in a way that can “show off your brainpower” but can’t be implemented.) Sometimes it’s difficult to tell if job-applicant homework is “just” a test, or if your work will end up in the company codebase. But if it’s obvious that the employer is processing candidates just to pick their brains clean of new ideas and IP, that’s probably not a place you want to work for.

The Interviewer Doesn’t Understand What You’re Doing

Many companies will follow up the homework assignment with a phone call or in-person interview, during which you and the interviewer will go over your answers. Frequently, you’ll end up with a hiring manager or programmer who knows their stuff, and is more than happy to tell you what you did right or wrong. Every so often, though, you’ll encounter an interviewer who doesn’t have the faintest clue—they’re clearly not a programmer, and chances are good they’re reading the answers off a sheet of paper. You can attempt to walk them through your thought process and solutions, but you might as well be speaking Urdu. Almost needless to say, if a company representative can’t talk to you on a technical level, something is very wrong with their process. React accordingly.

Conclusion

This isn’t to say that homework assignments are bad. Indeed, if done right, they’re an incredibly efficient way of deducing your true knowledge level, in a working environment that’s more “normal” than trying to write code on a whiteboard in a windowless office. But as with any kind of application process, there are potential downsides. (At least some companies will pay you to do homework, whether or not they hire you.)