I've conducted hundreds of interviews at Amazon and other tech companies. The hiring process may seem lengthy, but it's necessary.

Brandon Southern is a senior leader at Amazon and a former head of analytics at eBay and GameStop.

He says hiring managers have to be cautious when hiring because their reputations are on the line.

Southern says it's sometimes impossible to replace a bad hire because it's a time-consuming process.

Brandon Southern is a senior leader at Amazon and former head of analytics at eBay and GameStop.

He says a company might have to bring in 30 candidates for an initial screening to get three candidates that make it to the final round, to hire one person.

With only two to three interviewers, a hiring team will only hear a few examples of a candidate's experience.