Bias through selective inclusion and attrition: Representativeness when comparing provider performance with routine outcome monitoring data.
Edwin de BeursLisanne WarmerdamJos W R TwiskPublished in: Clinical psychology & psychotherapy (2019)
Estimates of provider performance were biased by selection, especially by missing data at posttest. Results on the extent and direction of bias and minimal requirements for response rates to arrive at unbiased performance indicators are discussed.