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Closer - The home of longitudinal research

Sample attrition

Sample attrition is when participants in a longitudinal study stop taking part over time. Attrition can reflect a range of factors, from study participants being untraceable, to them choosing not to take part when contacted. Problems that can stem from attrition include the potential to lead to bias in the study findings (if attrition is higher among some groups than others) and the reduction in the size of the sample as participants drop out.