Possible Clues:

• Joke attempt to trap detective giving expert opinion
• Spreading dirt in weak analysis
• Spreading dirt during weak commentary
• Joke I'd spun with attempt to show expertise
• Perhaps Shearer offers this nose around German and Italian training for starters
• Talking heads' opinions
• What talking heads are paid for
• The ability to speak authoritatively on a subject
• The giving of expert opinions
• Show of expertise that's weak about computers etc kept by doctor