HAWTHORNE Effect: A Methodological Problem in Growth Studies during Infancy

Abstract

Body weight and crown-heel length measurements were undertaken on 154 urban Punjabi infants by longitudinal and 721 comparable infants by cross-sectional methods. The growth attainments were comparable in the first 4/5 months, but after this age infants assessed by longitudinal method demonstrated significantly better growth attainments (p<0.05) as compared to those assessed by cross-sectional method. This pattern is explained on the basis of HAWTHORNE effect. It is recommended that the role of HAWTHORNE effect be considered while interpreting growth data from longitudinal studies.