Sources of Variation in Clinical Observations: Problems of Teaching and Some Results

The Wright Peak Flowmeter has proved a useful instrument to demonstrate to fourth year medical students in a three-hour practical class the sources of random and systematic variation arising in biological measurements. A learning effect and both instrument and observer bias including terminal digit preference were analysed by the students using a desk top computer to carry out simple statistical routines. The differing requirements of reproducibility and precision in epidemiological and routine clinical use were discussed.

Das Wright Peak Flowmeter hat sich als brauchbares Instrument zur Demonstration zufälliger und systematischer Schwankungen biologischer Messungen bei Studenten eines 3stündigen Seminars im 8. Semester erwiesen, Mittels eines elektronischen Tischrechners analysierten die Studenten selbst einen Lerneffekt sowie die instrumentellen Abweichungen und die Beobachter-Inkonstanz (einschließlich der Bevorzugung gewisser Endziffern), Die unterschiedlichen Anforderungen bezüglich der Reproduzierbarkeit und der Genauigkeit in epidemiologischen und klinischen Routineuntersuchungen werden erörtert.

Key-Words

Digit Preference - Peak Flow Meter - Observer Bias - Variation in Biological Measurements - ments.

Schlüssel-Wörter

Endziffernbevorzugung - Spirometer - Beobachter-Fehler - Variation biologischer Meßwerte.

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