Methods Published on 22 Aug 2017 Fitting the Fractional Polynomial Model to Non-Gaussian Longitudinal Data in Quantitative Psychology and Measurement Ji Hoon RyooJeffrey D. LongGreg W. WelchArthur ReynoldsSusan M. Swearer Frontiers in Psychology doi 10.3389/fpsyg.2017.01431 7,011 views 6 citations