"Dialectical Bootstrapping" is a simple procedure that may improve your estimates. This is how it works:
- Estimate the number in whatever manner you usually would estimate. Write that down.
- Assume your first estimate is off the mark.
- Think about a few reasons why that could be. Which assumptions and considerations could have been wrong?
- What do these new considerations imply? Was the first estimate rather too high or too low?
- Based on this new perspective, make a second, alternative estimate.
Herzog and Hertwig find that average of the two estimates (in a historical-date estimating task) is more accurate than the first estimate, (Edit: or the average of two estimates without the "assume you're wrong" manipulation). To put the finding in a OB/LW-centric manner, this procedure (sometimes, partially) avoids Cached Thoughts.