A study compared the performance of six cohorts of family physicians (711 practice-qualified physicians certified in 1971, 1972, 1973 and 1,233 residency-trained physicians certified in 1977, 1978, 1979) recertified in 1977-1991. Results indicate declines in performance on each recertification examination and better performance by residency-trained physicians. Further attention to examination design and recertification standards is recommended. (Author/MSE)