Interviews don't predict success, this might
Having interviewed thousands of people since 2006, I personally believe that interviews contribute around 5% to 10% of the data needed to make a good hire, yet many leaders still utilise them as their main selection tool.
Working with many different clients over the years, we have fine tuned their hiring processes and find the following works better than most.
Conduct the first interview differently
Keep it 30 minutes long
Interview with a colleague, ideally someone very different to you in personality to limit the halo effect.
Start out by asking the candidate what questions they have - provide no background or information.
This puts the candidate in control and at ease. The questions they ask and the order they ask them reveal what is important to them.
This gives you time to reduce confirmation bias because you are not asking questions that will confirm or deny your initial assumptions about the candidate.
Once the candidate has finished asking their questions, ask just one question: “What do you consider to be your proudest work achievement so far?”
Probe and ask for the detail: Over what time period? Who else was involved? What would you have done differently? etc.
Conduct cognitive tests
IQ and memory tests have value because research has shown that mental ability is one of the few consistent drivers of job success predictability.
Take at least 6 references
Take at least 6 references between the first and second interviews. Each reference should be taken over the phone, by you the hiring manager, and be 10 minutes long at most. This is a highly effective technique I can share in more depth if we work together and something I do on behalf of my clients.
Don't conduct multiple interviews instead...
I advise two options:
Devise a test that is as close to the actual day-to-day work as possible. If the job is to sell, can you create an environment and setting for that to take place?
Most serious candidates are happy to come in for a half day or full day. Bring them in for that period of time and get them to shadow peers and leaders because they are far more likely to relax and show their innate behaviours.