A Method for Obtaining an Unbiased Sample of Family Medicine Patients for Research Purposes

Abstract

Introduction: Obtaining a representative patient sample for research purposes can be challenging. Classic probability sampling can be trusted, but these approaches are not always feasible; yet alternatives may introduce bias. We summarize relevant literature, the need for new approaches, and illustrate a practical hybrid approach that could consistently produce representative patient samples.Methods: Valid approaches shift sampling decisions from fallible interviewers to less fallible reproducible processes. In lieu of the interviewer's inclination to select particular patients, we used the day of the week, the appointment time, and the sequence of the patient's last name in the alphabet to select a sample for a consent process and a survey.Illustrative Use: Characteristics of the study sample (n ‫؍‬ 225) were compared with the characteristics of the population (N ‫؍‬ 1964) that had an office visit during the recruiting period. The data suggested that the study sample was highly representative of the population in this illustrative case.Discussion: A hybrid sampling approach, in the context of a brief consent process, and a nonthreatening interview produced a representative study sample, but formal evaluation via simulation is needed to validate the hybrid approach. Convenience samples of consecutive patients should be avoided to minimize bias. (J Am Board Fam Med 2011;24:583-588.)

Sleep Duration, Quality, or Stability and Obesity in an Urban Family Medicine Center

“…14 The research assistant selected a patient according to time of the scheduled appointment (15 min or 45 min past the hour on Tuesdays and Thursdays, and on the hour or half hour on Mondays, Wednesdays, and Fridays). If more than one patient shared an appointment time, the research assistant chose the person to be interviewed based on the position of their last name in the alphabet.…”

Journal of the American Board of Family Medicine Sixth Annual Practice-based Research Network Theme Issue -They Just Keep Getting Better and Better

“…14,15 These "technique" papers include one on getting an unbiased patient sample. 16 Another highlights two quasi-experimental methods-a stepped-wedge design, and wait-list crossover design-that seem particularly useful in PBRN practices. 17 This rich-and enriching-issue is our salute to our many PBRN colleagues advancing primary care research in family medicine.…”