Documentation of referrals: recording bias due to patient insurance type

This study explores a possible association between the propensity of primary care physicians to record referrals on special referral forms and the source/mechanism of payment for services. Using a randomly selected sample of visits to University faculty family physicians over a 12-month period, referrals were identified from three sources: progress notes, a special form that was included in the patient's chart, and a computerized list that was generated from the special referral form. A notation in one or more of these sources constituted a referral. Using all three sources, the referral rates were 13.8 referrals per 100 patient encounters for Health Maintenance Organization (HMO) patients, compared with 14.1 for Preferred Provider Organization (PPO) patients and 10.4 for patients with other insurance (p = .83). The progress note in the patient chart was the best source for determining whether a referral had been requested, with approximately 85% documentation. Special forms were not likely to be completed for referrals, especially for non-HMO patients (less than 30% documentation). Thus, reliance on a special form for documentation of referrals would have led to the erroneous conclusion of higher referral rates for HMO patients. The tendency of providers to be more complete in recording referrals of HMO patients (a recording bias) may account for the observed higher rate of referral of such patients in other studies.