Cannot Measure Productivity

Martin Fowler argues that the software industry cannot reasonably measure productivity, which leaves many debates about process and design unresolvable. He says lines of code fail as an output measure because the same system can be written with very different line counts, and well-factored code is often shorter. Function points fare somewhat better, but he remains unconvinced, noting one system that counted differently by a factor of three across counters. He concludes that true productivity must be judged by delivered business value, and that even that is hard to measure because of time lags, so the field must admit its ignorance.