The aims of this project are 1.1) To measure the probabilities of attaining clinically significant therapeutic responses in JIA trial participants before week 16; 1.2) To measure the mean durations spent in each of the response states (ACRPedi response states/CID or JADAS states); 1.3) To identify predictors for the probability of attaining the different levels of clinically significant therapeutic responses; 2.1) To determine whether there are distinguishable latent classes of disease activity responses detectable before week 16 in trial subjects; and 2.2) To determine predictors of individuals’ membership in the latent classes of responses.