One can't measure something, much less discuss and downselect ways to measure that something, without first defining that something. This article doesn't define

One can't measure something, much less discuss and downselect ways to measure that something, without first defining that something. This article doesn't define productivity and only implicitly addresses what productivity might loosely mean. Productivity is often difficult to measure because no one ever defines it. It's no surprise that the ways to measure it as such are so diverse and often conflicting, because most are measuring something different. Productivity is a highly dynamic measurable that will change depending upon the tasks. Are the tasks adding new features, performing maintenance, fixing bugs, writing documentation, or what? A naive approach to productivity is to simply ask, are the things that people agreed upon needing to be done getting done? It seems a lot of these articles focus on software engineering alone, but I rarely, if ever, see reference to other industries. How do architects, designers, artists, professional engineers, hardware engineers, accountants, lawyers, etc. measure productivity? What makes software engineering so special?