Acceptable and recognized methods utilized to develop competency and prepare for occupational testing are strongly controlled by certifying agencies. Teachers, law enforcement officers, medical personnel and fire fighters, to name a few, operate under specific guidelines for training requirements to qualify for professional certification. Most certification examinations are competency based tests. What methods of preparation a certifying agency recognizes may severely restrict an individual's option to develop competency.;This research thesis specifically investigates fire fighter certification and methods of preparation to develop competency. Over five-hundred Iowa fire fighter candidates from 1989 to 1991 were studied. Written examination scores were collected along with various demographic information.;Specific hypotheses studied involved methods of preparation; years of experience; volunteer vs. career fire fighters; and gender of the candidates.