I've spent most of last week at work trying to perfect a grant proposal that pretty much everyone in our program has to sign off on. On Thursday, Friday and today there was a great deal of discussion about what metrics we could use to measure our outcomes, should we get funding.
It's actually not an easy question, as the project we're working on is a general good thing (patient education) designed to address a multitude of issues, as opposed to something more targeted.
Watching half a dozen people go back and forth about all this got me thinking about how often it is taken for granted that somewhere out there is a definition for "success" in various topics.
When I took a child development class in grad school, I remember in one of the first classes someone asked what the best parenting methods were. Our professor replied that there really couldn't be a consensus, because no one could agree on what would qualify as a success. He proceeded to use religion as an example: for parents of strong religious persuasion, a child who grew up a financially successful atheist would not necessarily be what they were going for. Conversely, secular atheist parents might be distressed at a strong religious conversion.
There are probably scores of good studies that could have been done on parenting methods if we actually had a definition of success we could all agree on. Too frequently, I think people overlook this point. The reason so many strange fads in parenting can get going is because it is really really hard to prove anyone right or wrong. Even if you try, you might just wind up with the dodo bird verdict.
If you can't agree on where you're going, you most certainly can't tell people how to get there. The studies you don't do are often as important as the studies you do.