The mythical software productivity miracle

We have got used to Moore’s Law, whereby hardware gets faster at a dizzying rate, though there ought to be a caveat to this that points out that software gets less and less efficient in tandem with this. A neat summary of this situation is “Intel giveth, and Microsoft taketh away”. However when it comes to software development, the situation is very different. Sure, things have become more productive for developers over the years. My first job as a systems programmer involved coding IBM job control language (JCL) decks, which entertainingly behaved pretty much as though they were still on punch cards, with all kinds of quirks (like cunningly ignoring you if you had a continuation of a line too far to the right, beyond a certain column). I just missed Assembler and started with PL/1, but anyone who coded IBM’s ADF will be familiar enough with Assembler. However it is not clear how much things have really moved on since then. In the 1980s “4GLs” were all the rage, but apart from not compiling and hence being slower to run, they were scarcely much advance on Cobol or PL/1. Then there were “CASE” tools like James Martin’s IEF, which promised to do away with coding altogether. Well, we all know what happened to those. Experienced programmers always knew that the key to productivity was to reuse bits of code that actually worked, long before object orientation came along and made this a little easier. Good programmers always had carefully structured code libraries to call on rather than repeating similar code by editing a copy and making minor changes, so I’m not convinced that productivity raced along that much due to OO either.

This is all anecdotal though – what about hard numbers? Software productivity can be measured in lines of code produced in a given time e.g. a day, though this measure has limitations e.g. is more code really better (maybe implying less reuse) and anyway how do we compare different programming languages? A more objective attempt was to measure the number of function points per day or month. This had the big advantage of being independent of programming language, and also works for packages – you can count the number of function points in SAP (if you had the patience). Unfortunately it requires some manual counting, and so has never really caught on widely beyond some diehards who worked in project office roles (like me). Well, we always used to reckon that 15-30 function points per man month was pretty much a good average for commercial programming, and when Shell actually measured such things back in the 1990s this turned out be pretty true, almost irrespective of whether you were using a 3GL or 4GL, or even a package. Shell Australia measured their SAP implementations carefully and found that the function points per man month was delivered was no better (indeed a little worse) than for custom code, which was an unpopular political message at the time but was inconveniently true. Hence, while 3GL productivity definitely was an advance on Assembler, just about every advance since then has had a fairly marginal effect i.e. programmer teams writing today are only slightly more productive than ones in 1986. By far the most important factor for productivity was size of project: big projects went slowly and small projects went quickly, and that was that.

A new book “Dreaming in Code” by Scott Rosenberg is a timely reminder of why this is. Many of the issues of writing a moderately complex application are not to do with individual programmer productivity and everything to do with human issues like a clear vision, good team communication, teamwork etc. All the faster processors and latest programmer tools in the world can only optimise one part of the software development process. Sadly, the human issues are still there to haunt us, having moved on not one jot. Scott discusses the Chandler open source project and its woes, reminding us that software productivity is only a little bit about technology, and a great deal about human nature.

When I was doing technology planning at Shell I always had a rule: if a problem was constrained by hardware then it would be fixed quicker than you expect, but if the problem was a software issue it would always take longer than you would think. This book tells you why that is not a bad rule.