Justifying not measurable initiatives

In my corpo-company (in which I believe 90% wrongly understands "measuring & metrics" term) I want to start an initiative. It's about to share best practices knowledge, coding quality importance, testing importance, DRY and KISS rules, etc.

My supervisors wants me to define some key metrics to measure the success of this initiative. I know, that they will evaluate me at the end of the year based on this metrics.

I believe that sometimes things can be measured, sometimes not, and sometimes the result is visible after long time (thus impossible to find cause-effect relation).

On the other hand, I want to avoid having some artificial, out of thin-air metrics (e.g. amount of pair-programming sessions done or decreased bugs found in code review) as this things may or may not be directly influenced by my initiative.

I'm struggling to express my thoughts to supervisors, as their focus on NUMBER and MEASURES is FUBAR. Can you suggest some articles, blogs or google key words that I can read and share that not everything in IT company should be measured? And not every initiative has immediate impact on metrics?

I already tried saying "you got what you measure" but despite they agreed, they didn't changed their approach.