Think about output

I'm a productivity guy. I want more output for each unit of resource.

But I know that you have to decide what is 'good' output.

A simple example. Ideally I want my mechanics standing around rather than fixing machines ... I don't want those machines out of action. So lots of output for the mechanics = bad news for me.

A more complex example. If we give teachers more students in their class, we get higher productivity ... or do we. What's the output, here?

Before you judge efficiency - and value, think about what you are trying to achieve. That's what you want more of.