I am often asked to provide an "e zero" estimate for a piece of work.

I have been assuming up to now that it means "rough estimate". Does anyone have any link to what this means specifically. I actually cannot find any reference to it on the web or on this site.

  • I have never heard of this in PM. I would assume someone means a zero error estimate but who knows. Sep 3 '19 at 12:37
  • @DavidEspina That's my best guess too, but I hope we're wrong. If I were asked to do that, my response would be "Okay, let me finish it first, and then I'll give you my estimate of how long it took."
    – Sarov
    Sep 3 '19 at 13:20
  • @sarov, it may be what is meant by zero. Absolute zero or results that are consistent with the estimated probabilistic estimate or frequency distribution. Maybe? I don't know. Sep 3 '19 at 14:03
  • It's possible this is an OPA (Organization Process Asset). If you have an intranet, run a search for it. Somewhere along the line someone may have created an estimation schema and called it "E Zero/E-Zero/EZero"... Sep 3 '19 at 15:12

Ask the person asking you.

This advice applies in general - whenever someone uses a term with which you are unfamiliar, ask them what it means.

This carries a slight risk of making you seem ignorant. Which is far better than the large risk involved when making an incorrect assumption, which can end up being costly to the project.

Not to mention, it's always possible that your business uses any given term to mean something entirely different from the norm.

When in doubt, ask. Not to strangers on the internet, but to the person who actually used the term.


E0 estimates are the estimated done on the basis of high level scope, usually done in sales cycle before the project starts.

E0 is revised after the project starts and requirement analysis is done. The project manager prepares E1 which is more firm estimates based on low level requirement discussions in the project requirement analysis phase.

  • Thanks. Had a hunch is was something like this alright.
    – orion_kid
    Sep 9 '19 at 12:25
  • Do you have a source for this? It would be nice to have... Sep 9 '19 at 20:29

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