What it corrects
The inside view builds a detailed story about this company, this team, and this plan. Detail feels rigorous, but it makes exceptionalism easy: every project has reasons it will be faster, cheaper, or more successful than the typical one.
The outside view starts elsewhere. It asks what happened across a reference class of comparable attempts, including failures and cancellations, then adjusts for the few facts that genuinely make this case different.
How it works
- Define the decision you are forecasting.
- Choose the closest useful reference class before defending uniqueness.
- Establish the base rate or normal range.
- Adjust conservatively for case-specific evidence.
In a Business Case Weekly case
In the Booking case, a compelling platform story is not yet evidence about distribution economics. The outside view asks how comparable intermediaries acquired supply and demand, what usually constrained them, and which case fact justifies a different expectation.
In your answer
- “Comparable attempts usually …”
- “This case differs because the evidence shows …”
- “I therefore move from the base rate to …”
Common misuse
A loose analogy is not a reference class. Choose comparables using the mechanism that drives the outcome, not the company’s surface category. The outside view is an anchor, not an excuse to ignore decisive local evidence.