Original Post Date: Friday, June 10, 2011

I’m on my way home from the ISPA/SCEA (International Society of Parametric Analysts, Society of Cost Estimating and Analysis) Conference held in Albuquerque this week.  Attendance was very good (2nd best in the conferences history) and as the content seemed especially good this week.  I attended lots of good talks on topics ranging from SEPM (System Engineering, Project Management) cost estimating, Joint Confidence Levels, Software Estimating, Affordability,  Agile software development and estimating for Enterprise Resource Planning Systems.   Of course, just because the topics are good and well presented doesn’t mean I have to agree with everything that gets said.

One particular talk entitled “Function Points, One Size Fits All” got me a little worked up.  It seems as though there is an on-going and completely unnecessary amount of energy devoted by some to convince the software community that we need to settle on a single method of measurement for software.  The author makes some really good, credible points.  Function Points are a much better method of measuring software if your intent is to compare productivity across or within specific industries.  They help eliminate development technologies, programmer inconsistencies and software architecture decisions from an analysis of how productive an organization is at delivering business value to their customers.

Having said this, I firmly believe that sometimes SLOC (Source Lines of Code) are a better tool to help organizations estimate the costs of the software development projects they are planning.  Knowing how your productivity stacks against the industry is great information when you are looking for process improvement or identifying best practices.  But if you want to know how much the next project is going to costor how many months it will  be before you can deliver content, your own history is much more relevant than the industries.  Not that your history can’t be in Function Points – it just doesn’t have to be.  Many of the weaknesses sighted with SLOC – while they certainly can be considered weaknesses) -aren’t really noticeable when working within a certain context.  Within an organization, software development projects are often similar to previous projects, targeted at similar markets and are being developed by similar teams with similar (on average) coding styles. And SLOC Counting processes can be institutionalized within an organization. When this is the case, SLOC counts are just as good, if not better, than Function Point Counts and probably much easier to count since their count can be automated and does not require certified specialists.

The author contends that SLOC is a bad option because it is hard to estimate early on.  I contend the same is true with Function Points - which if the Counting Practices Manual is followed to the letter – one is required to make an assessment of not only all transaction but also all the data element types and record element types.  The author contends that SLOC is a bad option because there is no standard for what a SLOC is.  I contend that the same can be said for Function Points.  Perusal of the International Software Benchmark Standards Groups’ (ISBSG) database shows that there are several different ‘standards’ for counting Function Points – because one standard was not deemed sufficient by many in the community to meet all software measurement needs.

Don’t get me wrong – I do not disagree with many of the assertions the author made, only the notion that one size fits all.  Let’s be real – software measurement is not easy and there are many different ways to approach it depending on the reasons for the measurement and the circumstances around those needs.  Function Points are a good tool to have in your software measurement tool box, so are Source Lines of Code, Use Case Points and user Stories.  It’s true that if all you have is a hammer every problem is a nail.  Fortunately we have many different tools and should feel empowered to choose the right tool depending on the current need.