There is no universal metric to gauge productivity of software engineers. The added value a software engineer produces with his work in a single unit of time h

There is no universal metric to gauge productivity of software engineers. The added value a software engineer produces with his work in a single unit of time has a huge variance. Furthermore, it can range from negative to positive. I.e, it does not matter how long one works. The only thing long work hours of a software engineer communicate is that they work long hours.