Apply your personal estimation ratio as a multiplier…

Apply your measured personal estimation ratio as a multiplier to all future estimates—if actual/estimated consistently = 1.8, budget tasks at 1.8× your initial estimate to achieve calibrated forecasting.

When This Fires

After completing Record estimate before and actual time after every 30+…'s two-week estimation tracking and having your ratio
When making any time commitment where accuracy matters
When combining with Three-point estimation (PERT estimation) for a fully calibrated estimate
When your estimation skill seems to have changed and you need to verify the ratio still holds

Common Failure Mode

Resisting the multiplier: "I know my ratio is 1.8, but this task is simpler than average, so I'll just use 1.2 this time." This is the planning fallacy reasserting itself — you're generating a special-case argument for why this time will be different. The ratio should be applied uniformly; the occasional over-estimate (when a task actually is simpler) is a small cost compared to the systematic under-estimation that results from selective application.

The Protocol

(1) Calculate your personal estimation ratio from Record estimate before and actual time after every 30+… data: average(actual / estimated) across all tracked tasks. (2) For each new estimate, first generate your intuitive estimate (let your brain do what it naturally does). (3) Multiply by your ratio: if intuitive estimate = 2 hours and ratio = 1.8, budgeted estimate = 3.6 hours. (4) Use the budgeted estimate for all planning, commitments, and scheduling. Do not use the intuitive estimate — it's the input, not the output. (5) Recalculate your ratio quarterly as you accumulate more data. If the ratio shrinks over time, your intuitive estimation is improving. If it remains stable, the multiplier is doing its job as a permanent correction.