I just read this article by @pauligle and I have to say it is extremely good with all the charts, as well.
My opinion on NCRs is that nobody actually likes them but they are very useful without a doubt. We are happy that today we have a tool like NCRs to measure our efficiency and improvement. Let’s not forget that only a few decades ago this was not the case and dodgy contractors and subcontractors could have gone away with everything in a construction project.