Principles are ways of successfully dealing with reality to get what you want out of life.
Ray Dalio, one of the world’s most successful investors and entrepreneurs, cites principles as his key to success.
The Issue Log is our primary tool for recording our mistakes and learning from them. We use it to bring all problems to the surface, so we can put them in the hands of problem solvers to make systematic improvements. It acts like a water filter that catches garbage. Anything that goes wrong must be "issue logged" with the severity of the issue and who is responsible for it specified, so that it's easy to sort through most problems. Issue logs also provide paths for diagnosing problems and the information pertaining to them. In that way, they also provide effective metrics of performance, as they allow you to measure the numbers and types of problems coming up (and identify the people who are contributing to them and fixing them).
The Issue Log is a good example of a tool that changed habits and perceptions. A common challenge people had at first was openly pointing out mistakes, because some people instinctively viewed pointing out mistakes as hurtful to the people who made them. Once they got used to doing this, they realized the benefit of it and they got in the good habit of doing it. Now most people can't do without it.