I guess it depends on whether you want to make a difference, ergo reduce accidents. I would start with hiring trends, 200 hour FOs sitting in large airliners. The effect of unions/management on missed maintanance(SW/Alaska Airlines). Flex/Assumed/Reduced thrust SOPS: Risk vs Reward. Trend monitoring with result of flying around on 35000 engines...risk vs reward. GO no Go decisions could always get a revisit, given some people will just GO no matter what...