This morning, I heard from a young designer who is looking for her first design job in San Francisco. She’s truly talented and she has a strong portfolio, so she is interviewing at over a dozen companies in Silicon Valley.

Yesterday, two separate companies asked her to do quick take-home demo projects to show her design thinking and her abilities. Great! What an opportunity to flex her muscles and show her skills first-hand.

Unfortunately, both companies asked her to do demo projects on their own product which (rightly!) makes her feel a bit queasy.

Dear entrepreneurs and hiring managers, let me explain why this all-too-common practice is both unfair and, even worse, ineffective.

Unfair?

Simply put, it’s unfair to ask someone to do real work for free. It’s especially unfair to ask someone to do real work for free when you’re dangling a carrot in front of them: “Just do this one little project and then maybe you’ll get a great job with our company!”

These designers often have no job at the moment, really need the work, and won’t get any value out of the exchange (i.e. learning).

But, you say, “it’s not real work, it’s just a demo!” I know you think that. And you believe it wholeheartedly. But if the designer comes up with a clever solution, do you really think that even a little part of your unconscious can resist adopting that solution?

Even if you believe with all your heart and intellect that you can firewall your thoughts, there is no way for the designer to know this other than to blindly trust you. And, it’s unfair of you to ask for that one-way trust.

Regardless if you think you are acting fairly, many great designers don’t agree with you. So, when you ask a great candidate to do a demo project on your own product, they might just walk away.

Or, you might not even hear the designer say anything against you. She might quietly, grudgingly do the project and then choose to decide to work for another company with higher standards of fairness.

Either way, you lose for skating on a thin ethical line.

Ineffective?

I may not convince you that this practice is unfair, but frankly that won’t keep me up at night because the more important thing to know is that it is simply ineffective.

You know a lot about your own product. You know things that are proven to work, things that were tried and didn’t work, things that are easy or hard to implement, things that are inextricably linked in the product, and things that seem promising that your team is currently considering.

You’re also heavily biased towards decisions that you helped make.

When an outside designer comes in and makes suggestions, you will immediately see the holes. “But, isn’t that great? That will help me choose the best candidate!” Not really.

The designer is identifying the most promising solutions that she can see. You have an unusual vantage point, so you can’t visualize the designer’s outside perspective — her solutions are possibly the most likely solutions with the data available to her.

In the end, you will choose the candidate who just happens to try solutions that align with your perspective. That’s a matter of chance, not a matter of ability.

Instead, work together in-person on a great challenge

Test exercises are great! Immediately after a designer’s portfolio, I think that in-person design exercises are the second best way to gauge a designer’s skills.

You’re not hiring a designer who goes off into a corner to magically create perfect solutions like she can read your mind. You are hiring someone who can work with a team to identify the right problems, create the best solutions, and test the real-world effectiveness of those choices.

So, work on a design exercise with the candidate and you will learn much more about her abilities.

Braden Kowitz, a design partner at Google Ventures, has written a superb and thorough article on How to interview a designer with the perfect design exercise. He outlines several possible exercises that will help you determine a candidate’s thought process, overall ability, and preparedness to work well on a team — all critical for hiring the right person and few of which you’ll get from a take-home demo project on your own product.