Selection Bias

Also known as: Sampling Bias, Interview Bias

The distortion introduced when the people interviewed are not representative of the target population.

Full Definition

Selection bias occurs when the sample of interviewees is systematically different from the market the team is trying to understand. Common sources include interviewing only enthusiastic early adopters, only contacts referred by a single champion, or only institutions with characteristics (budget, technology, culture) that differ from the broader market. Selection bias can produce findings that are accurate for the sample but misleading about the market.
Example
A team interviews 12 clinicians, all from academic medical centers referred by a single KOL. Their findings strongly validate the problem. When they reach community hospitals — which represent 80% of their target market — the problem barely registers.