title: Time-series panel analysis (TSPA): multivariate modeling of temporal associations in psychotherapy process.
abstract: OBJECTIVE
  Processes occurring in the course of psychotherapy are characterized by the simple fact that they unfold in time and that the multiple factors engaged in change processes vary highly between individuals (idiographic phenomena). Previous research, however, has neglected the temporal perspective by its traditional focus on static phenomena, which were mainly assessed at the group level (nomothetic phenomena). To support a temporal approach, the authors introduce time-series panel analysis (TSPA), a statistical methodology explicitly focusing on the quantification of temporal, session-to-session aspects of change in psychotherapy. TSPA-models are initially built at the level of individuals and are subsequently aggregated at the group level, thus allowing the exploration of prototypical models.
  
  
  METHODS
  TSPA is based on vector auto-regression (VAR), an extension of univariate auto-regression models to multivariate time-series data. The application of TSPA is demonstrated in a sample of 87 outpatient psychotherapy patients who were monitored by postsession questionnaires. Prototypical mechanisms of change were derived from the aggregation of individual multivariate models of psychotherapy process. In a 2nd step, the associations between mechanisms of change (TSPA) and pre- to postsymptom change were explored.
  
  
  RESULTS
  TSPA allowed a prototypical process pattern to be identified, where patient's alliance and self-efficacy were linked by a temporal feedback-loop. Furthermore, therapist's stability over time in both mastery and clarification interventions was positively associated with better outcomes.
  
  
  CONCLUSIONS
  TSPA is a statistical tool that sheds new light on temporal mechanisms of change. Through this approach, clinicians may gain insight into prototypical patterns of change in psychotherapy.
authors.affiliation: Department of Psychotherapy.
authors.forename: Fabian
authors.initials: F
authors.lastname: Ramseyer
authors.affiliation: Department of Psychotherapy.
authors.forename: Zeno
authors.initials: Z
authors.lastname: Kupper
authors.affiliation: Department of Clinical Psychology and Psychotherapy, University of Bern.
authors.forename: Franz
authors.initials: F
authors.lastname: Caspar
authors.affiliation: Department of Clinical Psychology and Psychotherapy, University of Bern.
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Znoj
authors.affiliation: Department of Psychotherapy.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Tschacher
mesh_terms: D000328:Adult; D030141:Feedback, Psychological; D005260:Female; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D013811:Psychotherapeutic Processes; D011613:Psychotherapy / Q000379:methods; D020377:Self Efficacy; D057566:Self Report; D013997:Time Factors