The assumption in most organisations is that interviewing is a natural skill. It is not.
Untrained interviewers introduce bias early
Without preparation, interviewers default to familiarity bias within the first three minutes. They respond to confidence, accent, or shared background rather than evidence of competence. This is not a character flaw. It is what happens when someone walks into a high-pressure conversation without a framework. Businesses that track this through structured scoring sheets see a clear pattern: unprepped interviewers cluster scores around gut reaction rather than role-specific criteria.
What a preparation experiment looked like in practice
One mid-sized professional services firm ran a six-month test. Two hiring managers used a standard unstructured approach. Two others used a preparation protocol: competency mapping, written questions submitted in advance, and a mandatory solo debrief form before group discussion. The firm also used a news feed portal to distribute updated role briefs and panel notes in real time. The structured group made offers that resulted in longer average tenure in the first year. The unstructured group had a higher rate of early-stage departures.
The common mistake underneath all of this
Businesses invest heavily in employer branding and sourcing, then hand the final decision to an undertrained panel with 20 minutes of prep time. The interview is the highest-stakes moment in the hiring process. Treating it as a formality rather than a skill-based activity is where most hiring errors originate. Preparation is not about scripting the conversation. It is about giving interviewers enough structure to make a consistent, defensible decision.