Monday, September 19, 2011

5 steps to estimate software development time

Here's an oldie but a goodie from my personal blog summarized for you here:

Estimating software development time is really, really hard. Here's my method:
  1. Come up with your best, realistic estimate using your favorite technique.
  2. Ok, you have your absolutely realistic number now, right?
  3. It's not realistic. There are aspects you haven't thought of. Double the number. This is your best case scenario estimate, if there are no snags or major changes along the way.
  4. Now double it again. This is your most likely estimate. This is how long the project will probably take.
  5. Now double it a final time. This is your worst case scenario. This is how long is might take if you run into several major issues.
So to sum up:
  • E = Your original time estimate
  • 2(E) = Best case scenario time in reality
  • 4(E) = Most likely time in reality
  • 8(E) = Worst case scenario time in reality
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