Linear Regression to Approximate Longitudinal Growth Curves: Revised Standards for Velocity of Weight and Length in Infants

Abstract

Summary: Because of lack of acceptability of the previous log-linear model of slope velocity for the assessment of weight and length in children 1 to 36 months of age, a modified method for least squares determination of velocity of growth by slope has been designed. This model uses a compound logarithmic expression of tune and a newly designed graphic scale. The acceptability of the graphic (hand-drawn) line is retained while “goodness of fit” of the model is improved. This improved model makes it possible to revise our standards for velocity of growth of children 1 to 36 months of age. Speculation: When applied to clinical situations of abnormal growth, this model shouldhelp in the evaluation of patient growth. Along with the previously developed model for children 3 to 12 yr of age, it will form the basis for new office charts for the practitioner.