we can't find any numerical parameter that is predictably increased by evolution
The chances of successful transmission of genes across generations given a stable environment. The number of offspring surviving to reproductive age is a good first-order approximation.
If you want something more tangible, predictions what features evolution would lose are rather easy -- those that are (energy-)expensive and are useless in the new environment.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.