The best replacement for efficacy is effectiveness.

The best alternatives to efficacy are rated as following:
★★★★★  effectiveness
★★★★  efficiency
★★★★  potency
★★  self esteem
★  affinity
★  effective
  self confidence
  effectivity
  esteem
  confidence
  efficiency lighting
  potency pharmacology
  efficacity
  intrinsic activity
  effectiveness difference
  self-confidence
  locus of control
  self concept
  treatment effectiveness

Your alternative for efficacy is not listed? Suggest!


No companions for efficacy have been suggested so far.
You have in mind a companion for efficacy and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of efficacy in all years. Click on graph for more.
efficacy
effectiveness
efficiency