Avoiding the Watermelon Effect

The watermelon effect occurs when a service looks green outside and red inside: headline targets are met while poor experience, recurring risk or harmful variation stay hidden. Avoiding it means looking at distributions, exceptions and consumer feedback, not just whether targets were hit.

• Review distributions and exceptions rather than averages alone, starting with one priority service.
• Compare SLA status with complaints and consumer effort, and expose excluded and failed journeys so that local efficiency does not mask end-to-end failure.
• Invite qualitative challenge from the people who perform and receive the work. In the article's example, monthly availability is green while one critical business window repeatedly fails, giving a red experience to the users who matter most at that time.
• Track green metrics with red feedback, exception impact and hidden failure demand as a set. Use green metrics with red feedback as the starting signal, but compare it with exception impact before deciding whether an intervention worked.
• Avoid treating target achievement as proof of health, silently excluding difficult cases, and using averages without looking at the tails. Evidence of a risk should lead to an owner and a proportionate action, not merely another note in a report.