analysesanalysisassessingassociationbayesianbiasclinicaldatadesigndesignsdrseffectivenessevaluatingevaluationintentionlachinlittlemdmeurermissingmodelsmultiplenonparametricnortonobservationalrandomizedrealregressionresearchresultssequentialstudiesstudytesttimetreattreatmenttreatmentstrialtrialsuseusingworld