[Data quality in the MORBUS Sentinel Project--expiratory wheezing in infants].

Since 1991 the MORBUS project is being conducted to establish and run a sentinel network of 100 general and paediatric practices in three regions of Germany. A number of health conditions have been and will be monitored consecutively with special emphasis on environmentally determined health problems. From March to June, 1991, 1054 contacts of 1- and 2-year-old children with expiratory wheezing were reported. Quality of these event data was assessed by means of internal completeness. Important clinical information was missing in about 10% of all cases without evidence for regional differentiations. Data quality by this criterion was better in first contact than in re-contact cases (9.7% vs 18.1% missing). Questions concerning the parents (allergies, smoking, education) were less frequently answered (up to 24% missing) than questions of obvious medical relevance to the child. Completeness of parental information varied considerably between regions. There was no association between the medical specialty of the doctors and the quality of their data. In a longitudinal view, there was a slightly positive trend over time in the proportion of clinically incomplete case reports at borderline statistical significance (p = 0.057). Apart from these minor findings then, there was an overall good consistency of completeness in the MORBUS data on expiratory wheezing. By optimizing questionnaires and data transmission, it should be possible to increase the data quality even further.