How I make very early software cost estimates (Part 1)

Summary: I use Function Point Analysis (FPA) and Yesterday’s Weather to make “back of the envelope” software cost estimates when discussing potential new software projects with decision makers.

The problem

Many times when a software project is in its earlier stages (the conceptualization phase), the people that control the money at an organization (the CEO, CFO, CIO, etc.) want the best estimate they can get regarding the time and cost of a software development project. This is often very early in the project lifecycle, typically shortly after someone said, “Hmm, that sounds like a very interesting idea” and well before the first check is cut. In short, they want the best back of the envelope, ballpark cost estimate you can give them.

The solution

I used to dread these discussions, because I hated estimating the time and cost of software projects. I wasn’t any good at it, and the developers I worked with weren’t any good at it either. But once I learned two things: