Do on-site patient satisfaction surveys bias results?

BACKGROUND: Response rates, patient sample characteristics, and patient satisfaction ratings were compared between two surveying methods: (1) surveys completed at the physician office site (on-site surveying), and (2) surveys mailed to patient homes following the encounter (mail-out/mail-back).
METHODS: Surveying was completed at three physician practices within a 214-physician medical practice. Patients with physician appointments during four-hour time blocks were randomly split to receive either on-site or mail-based satisfaction surveys.
RESULTS: Participants younger than 45 years of age provided much higher satisfaction ratings on site than they did by mail (p < .0001), and participants older than 45 years of age reported satisfaction levels consistently whether on site or by mail. Both age groups reported higher satisfaction with "people aspects" of care on site than they did by mail (p < .001). DISCUSSION: On-site methods may yield satisfaction results that are biased in a positive direction for younger patients and for all patients in which social desirability pressures are prominent. Therefore, organizations that rely on such information may have an inflated view of the patient's satisfaction with their care delivery experience. Secondly, because the differences in ratings are the greatest for the "people aspects" of care, if improvement efforts are prioritized on the basis of these rapid results, the wrong priorities may be set.