I am completely against metrics for posteriori analysis of projects. It simply doesn't work on a personal level.
I use metrics as a tracking tool of success because my perceptions can be deceiving sometimes. Replying to the first post, metrics is/was more important than successful outcome for me in many times. I suggest George Leonard's Mastery book for more on that.
The successful outcome of a project is essential to plan your actions and make sure you are on track. But in the real field, it is often difficult to refer to some higher level definition of success, and that is when metrics become useful. This is so powerful that it has been used in very critical situations, such as addiction recovery. While the higher level outcome is clear (getting rid of the addiction and staying health), one generally needs a day-to-day metrics (just for today, I will have zero of this in my body).
So I have incorporated this in my successful outcome definitions and always look for something measurable to help me on the field. Here goes some examples:
- Outcome: buy a nice house / Metrics: inspect at least 2 houses per week;
- Outcome: be healthy / Metrics: run for 1/2 hour at least 3x/week;
- Outcome: write a book / Metrics: get at least 1 hour of quality writing per day.
The common idea here is simple: although a lot can happen during your project, there are always some obvious measurable things that if not done will put your outcome at risk. But don't try to make it perfect and don't be too harsh on yourself on your weekly review (which is a kind of cleansing ritual, isn't it?).