In recent days, I have been working closely with Craig larman to bring out a new domain modal based on scrum for Valtech cockpit. During the discussion with Craig, he talked about how stakeholders ask for % completion of the project and, how our PMs give them a %(percentage) !! It all looks idiotic if you read the rest of the following section.
The core reason for introducing agile methods in software is to manage the changes, adapt accordingly and be open to get changes. As per the statistics, change requests increases as the project size increases. If we are getting more changes obviously it would add more effort to existing estimated effort and this becomes a moving target. How can anybody estimate how much % of project has completed in this scenario? It is as good as telling not the truth, if I tell my stakeholder that we have finished 50% project !! (Unless you add a clause saying "as of today")
So, instead of using "% Complete" as the measurement, one can use the "estimated effort" remaining to complete the project