[The informational value of L1 statistics required as of 1988 (Federal Law IV) exemplified by an orthopedic university clinic].

1986's data of 2,428 hospitalised cases resp. 1762 patients were evaluated. The three codes most frequently used based on ICD-9 (715, 717 and 722) were separately considered. Repeated admissions to the hospital, patient age and duration of hospitalisation were analysed with reference to diagnoses. Analysis of covariance presented a weak correlation between age and length of stay for the ICD-9-codes 715 and 722. The encoding of diagnoses by different physicians proved to be unreliable and non-uniform. Therefore the encoding process should be centralized. Interpretation has to be made after careful examination of data. The results of more comprehensive statistics may be useful for negotiations concerning hospital allowance.