title: Empirical Bayes MCMC estimation for modeling treatment processes, mechanisms of change, and clinical outcomes in small samples.
abstract: OBJECTIVE
  The current analysis demonstrates the use of empirical Bayes (EB) estimation methods with data-derived prior parameters for studying clinically intricate process-mechanism-outcome linkages using structural equation modeling (SEM) with small samples.
  
  
  METHODS
  The data were obtained from a small subsample of 23 families receiving Functional Family Therapy (FFT) for adolescent substance abuse during a completed randomized clinical trial. Two or 3 video-recorded FFT sessions were randomly selected for each family. The middle 20-min portion of each session was observed and coded. An SEM examining the influence of a select set of observed therapist behaviors on pre- to posttreatment change in mother reports of family functioning and, in turn, pre- to posttreatment change in adolescent reports of adolescent marijuana use and delinquent behavior was specified. The SEM was implemented using EB estimation with data-derived maximum likelihood (ML) prior parameters and Markov Chain Monte Carlo (MCMC) estimation of the joint posterior distribution.
  
  
  RESULTS
  The EB SEM results indicated that a relatively high proportion of individually focused general interventions (i.e., seek information, acknowledge) as well as relationally focused meaning change interventions by therapists during sessions of FFT were predictive of pre- to posttreatment increases in levels of family functioning as reported by mothers in families of substance-abusing adolescents. In turn, increases in mother-reported family functioning were predictive of reductions in levels of adolescent-reported delinquent behavior.
  
  
  CONCLUSIONS
  EB MCMC methods produced more stable results than did ML, especially regarding the variances on the change factors in the SEM. EB MCMC estimation is a viable alternative to ML estimation of SEMs in clinical research with prohibitively small samples.
authors: Oregon Research Institute.
authors: Timothy J
authors: TJ
authors: Ozechowski
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D001499:Bayes Theorem; D005196:Family Therapy; D005260:Female; D006801:Humans; D008297:Male; D008390:Markov Chains; D009010:Monte Carlo Method; D016032:Randomized Controlled Trials as Topic; D019966:Substance-Related Disorders / Q000628:therapy*