Research and Statistics: Distinguishing Statistical Significance from Clinical Importance: The Value of the P Value

1. Sharon R. Ghazarian, PhD* 1. *Director, Bayview Biostatistics, Epidemiology and Data Management Core, Department of Pediatrics, Johns Hopkins University, Baltimore, MD. You have been providing handouts on infant massage to your families who have newborns for several years. You had read about the benefits of infant massage, including increased bonding between parent and child, improved infant digestion, facilitation of attachment, improved sleep, and better infant weight gain. (1) However, you recently read an article showing the results of a comparative panel design study in which the association between infant massage and weight gain was statistically significant at 2 months but not at 4 months of age for mothers and their infants in Santiago, Chile. (2) You now wonder whether infant massage is as beneficial as you once thought and whether you should continue to provide the information to parents of newborns. Many practitioners wonder whether a lack of statistical significance means a lack of clinical importance for their patients. If …