People may be interested in this open BMJ journal article:
Effectiveness of interventions to reduce ordering of thyroid function tests: a systematic review.
by: Zhelev Z, Abbott R, Rogers M, Fleming S. et al
BMJ open 2016:6:e010065. doi;10.11364/bmjopen-2015-010065
It goes through the findings of several papers relating to guidelines, policy, education, decision aids, feedback.
The results are not encouraging as regards consistency in these aspects