I’ve got a question about how others do estimating and then use those estimates in their portfolio planning process. If you estimate the cost and a finish date on an IT project (or really any project for that matter) and over the course of working the project, conditions change where the estimates are no longer valid, how do you handle the change? Do you revise estimates along the way and then have the resulting situation where the final product ‘meets’ your new revised estimates? Or do you hold yourself accountable to your original estimates from the very beginning?
If a group is serious about trying to get the estimates right in the first place and then measuring accuracy over the course of months, quarters and years, how you answer this question is very important. It seems that you must hold yourself accountable to your first estimates because they are the ones that were used to make a go/nogo decision in the first place. Furthermore, you want to setup a closed loop process where you try to shrink the gaps over time and minimize errors as you get better at estimating.
This breaks down when events beyond the control of the team affect the project. Perhaps an unexpected M&A effort effects everything or changes in leadership dramatically change priorities on the portfolio. In situations like these, the original estimates can be meaningless.
Also, you are learning things as you go along. Conditions change, priorities change, people leave, etc. Somehow you need to account for these learnings along the way so you can always provide the best estimate possible as your progress through the project.
I saw a recent report that talked about the need for IT shops to get better at estimating. Seems like I need to get a good answer on this question first.
I’d be curious how other address this?