Simon Willison’s Weblog

Why is software effort estimation still based on thumb rules and gut feels? How come no one has come up with an accurate estimation model?

13th October 2010

My answer to Why is software effort estimation still based on thumb rules and gut feels? How come no one has come up with an accurate estimation model? on Quora

For a truly accurate estimation, you need to have built the software before. If you’ve built it before, why are you building it again?

Posted 13th October 2010 at 5:06 pm · Follow me on Mastodon, Bluesky, Twitter or subscribe to my newsletter

More recent articles

JustHTML is a fascinating example of vibe engineering in action - 14th December 2025
OpenAI are quietly adopting skills, now available in ChatGPT and Codex CLI - 12th December 2025
GPT-5.2 - 11th December 2025

This is Why is software effort estimation still based on thumb rules and gut feels? How come no one has come up with an accurate estimation model? by Simon Willison, posted on 13th October 2010.

software-engineering 60 web-development 169 quora 1005 product-management 9

Next: Who is the most recognizable person in the world (real or fictional; alive or dead)?

Previous: Simon Willison: How do you configure the Apache server you describe in What are the advantages of running Apache behind nginx as opposed to just Apache by itself?

Monthly briefing

Sponsor me for $10/month and get a curated email digest of the month's most important LLM developments.

Pay me to send you less!

Sponsor & subscribe