I was an intelletual rebel in college, which my professors either loved or loathed. I read a good deal of Carl Rogers because I found a kinship there that I am still only realizing. Detractors of Rogers always bring up the fact that though he was extremely effective at interventions, his methods and results could not readily be replicated by others. It was finally determined that his methods worked for him because of Carl's personal efficacy.
I have found the same is true for many people. It is politically incorrect to say so, but some people are better at some things than others, and that this difference in all of us cannot be fully made up for by education or experience. You have likely seen it in the difference between great teachers and adaquate ones. It is not typically just a function of things like persistance, education, or desire. You either have this efficacy as a part of you or not.
Here is some research that indicates some in-born characteristics that prove very useful when looking for interventionists. A program (especially when working with families) can flourish or die on the efficacy of the person leading it. Carl Rogers is avenged!
I produced this abstract using time paid for by the Quay County Maternal Child and Community Health Council with funds from the New Mexico Department of Health.The effectiveness of the program is highly dependent on the trainer’s efficacy and characteristics. Although little data exist on how much of the effectiveness of a family program can be attributed to the trainer versus the standardized curriculum, estimates indicate that program effectiveness is 50- to 80-percent dependent on the quality of the trainer. Qualitative evaluations of trainer effectiveness, participant satisfaction ratings, and long-term followup interviews with participants (Harrison, Proschauer, and Kumpfer, 1995) delineated nine important staff characteristics for program effectiveness: