A heap of studies show unstructured job interviews are basically useless, and that popular questions about weaknesses, strengths, and imagined career trajectories accomplish close to nothing when it comes to choosing the best candidate for a role.

What's the solution? Many a management expert (including even Google's former people chief Laszlo Bock) has suggested behavioral questions. These are the type of questions that ask you to recall and dissect some incident from your past professional life. They usually start with "Tell me about a time you had to ... "

They seem more useful than curveballs about how many golf balls fit in a bus and less obviously open to BS than "Why do you want to work here?" But according to one star business school professor at least, this popular alternative is actually fatally flawed as well.

3 reasons behavioral interview questions are a bad idea

On his blog recently (hat tip to Quartz), Wharton School professor and best-selling author Adam Grant offers three reasons why this oft-recommended style of interview question is actually far less effective than many people believe:

(a) They're unfair--they give an advantage to candidates with richer experience. Ask a bunch of applicants how they handled a serious conflict with a colleague, and odds are you'll get a better answer from the one who happened to face the biggest conflict.?

(b) They're too easy to game--you end up hiring the candidate who's the best talker, not the best contributor.?

(c) They're not tailored to your organization or the job--they're stuck in what applicants have encountered in the past, not what they're going to do for you in the future.

Or to sum up Grant, the trouble is that while behavioral interview questions might give you insights into what people have done in the past, they don't tell you much about what they'll do in the future, how they're capable of growing, or how they'll react to new challenges specific to your company.

A better alternative

So what will? If you're looking for a better way to get at a candidate's capabilities and approach to problems, swap the past tense for a hypothetical, Grant suggests, recommending "situational questions." These begin with "what would you do if ... " and are "especially good for assessing leadership and interpersonal skills," notes Grant, though they can be used to more accurately assess a whole host of skills.

"For example, to assess persuasive skill, I've often asked them how they would sell a rotten apple. And to spot an original thinker, I like to ask candidates how they would improve our interview process," Grant offers.

Have you found behavioral interview questions to be an effective way to assess candidates?