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Estimating using FPA and Hours/FP(Introductory note: On my web site I've provided several online tutorials regarding Function Point Analysis (FPA), so if you're not familiar with it, I recommend learning about it before you read this section. See the References section of this document (section 9) for links regarding FPA and the International Function Point User's Group.) Because I've worked with this development team on estimates before, and because they are working with only two new technologies that are actually mature, I can use their productivity rate from previous projects to estimate this project. For instance, when this team has worked with this form of requirements specification, their productivity rate on other web development projects has averaged 4.0 hours/FP. Some have been as low as 3.7 hours/FP, others as high as 4.5 hours/FP, but 4.0 hours/FP has been the average. Looking at their data, any time any new technologies have been added to the mix their overall productivity rate has actually decreased, not increased. On subsequent projects their appears to be a slight payoff for the new technologies, but on projects where significant new tools have been added the team has generally slowed down. Finally, there is the matter of the new developer being added to the team. While some people will argue that this will make the team faster, I disagree, especially initially. I could be more of a pessimist and say that the new developer may in fact slow the team down, but as a general practice, when a new developer is first added to a team, for the purposes of estimating I just treat them as if they weren't there.
Looking through the team's historical data, and knowing that two new technologies are being added to the equation, I believe the team will proceed more slowly than their 4.0 hours/FP average and tend more toward their 4.5 hours/FP high. At a 5
Therefore, 4.2 hours/FP times 750 hours is 3,150 hours. With four developers on the team (not including the new person), and assuming all four can work on the project simultaneously (a pretty big assumption), I divide the 3,150 hours by four, which leads to 787.5 hours per developer.
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