Intraclass correlation associated with therapists: estimates and applications in planning psychotherapy research.

It is essential that outcome research permit clear conclusions to be drawn about the efficacy of interventions. The common practice of nesting therapists within conditions can pose important methodological challenges that affect interpretation, particularly if the study is not powered to account for...

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Main Authors: Baldwin, SA, Murray, D, Shadish, W, Pals, S, Holland, J, Abramowitz, J, Andersson, G, Atkins, D, Carlbring, P, Carroll, K, Christensen, A, Eddington, K, Ehlers, A, Feaster, D, Keijsers, G, Koch, E, Kuyken, W, Lange, A, Lincoln, T, Stephens, R, Taylor, S, Trepka, C, Watson, J
Format: Journal article
Language:English
Published: 2011
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author Baldwin, SA
Murray, D
Shadish, W
Pals, S
Holland, J
Abramowitz, J
Andersson, G
Atkins, D
Carlbring, P
Carroll, K
Christensen, A
Eddington, K
Ehlers, A
Feaster, D
Keijsers, G
Koch, E
Kuyken, W
Lange, A
Lincoln, T
Stephens, R
Taylor, S
Trepka, C
Watson, J
author_facet Baldwin, SA
Murray, D
Shadish, W
Pals, S
Holland, J
Abramowitz, J
Andersson, G
Atkins, D
Carlbring, P
Carroll, K
Christensen, A
Eddington, K
Ehlers, A
Feaster, D
Keijsers, G
Koch, E
Kuyken, W
Lange, A
Lincoln, T
Stephens, R
Taylor, S
Trepka, C
Watson, J
author_sort Baldwin, SA
collection OXFORD
description It is essential that outcome research permit clear conclusions to be drawn about the efficacy of interventions. The common practice of nesting therapists within conditions can pose important methodological challenges that affect interpretation, particularly if the study is not powered to account for the nested design. An obstacle to the optimal design of these studies is the lack of data about the intraclass correlation coefficient (ICC), which measures the statistical dependencies introduced by nesting. To begin the development of a public database of ICC estimates, the authors investigated ICCs for a variety outcomes reported in 20 psychotherapy outcome studies. The magnitude of the 495 ICC estimates varied widely across measures and studies. The authors provide recommendations regarding how to select and aggregate ICC estimates for power calculations and show how researchers can use ICC estimates to choose the number of patients and therapists that will optimize power. Attention to these recommendations will strengthen the validity of inferences drawn from psychotherapy studies that nest therapists within conditions.
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spelling oxford-uuid:68b65a67-895e-4b4e-b9e5-e7fbb649bd772022-03-26T18:46:53ZIntraclass correlation associated with therapists: estimates and applications in planning psychotherapy research.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:68b65a67-895e-4b4e-b9e5-e7fbb649bd77EnglishSymplectic Elements at Oxford2011Baldwin, SAMurray, DShadish, WPals, SHolland, JAbramowitz, JAndersson, GAtkins, DCarlbring, PCarroll, KChristensen, AEddington, KEhlers, AFeaster, DKeijsers, GKoch, EKuyken, WLange, ALincoln, TStephens, RTaylor, STrepka, CWatson, JIt is essential that outcome research permit clear conclusions to be drawn about the efficacy of interventions. The common practice of nesting therapists within conditions can pose important methodological challenges that affect interpretation, particularly if the study is not powered to account for the nested design. An obstacle to the optimal design of these studies is the lack of data about the intraclass correlation coefficient (ICC), which measures the statistical dependencies introduced by nesting. To begin the development of a public database of ICC estimates, the authors investigated ICCs for a variety outcomes reported in 20 psychotherapy outcome studies. The magnitude of the 495 ICC estimates varied widely across measures and studies. The authors provide recommendations regarding how to select and aggregate ICC estimates for power calculations and show how researchers can use ICC estimates to choose the number of patients and therapists that will optimize power. Attention to these recommendations will strengthen the validity of inferences drawn from psychotherapy studies that nest therapists within conditions.
spellingShingle Baldwin, SA
Murray, D
Shadish, W
Pals, S
Holland, J
Abramowitz, J
Andersson, G
Atkins, D
Carlbring, P
Carroll, K
Christensen, A
Eddington, K
Ehlers, A
Feaster, D
Keijsers, G
Koch, E
Kuyken, W
Lange, A
Lincoln, T
Stephens, R
Taylor, S
Trepka, C
Watson, J
Intraclass correlation associated with therapists: estimates and applications in planning psychotherapy research.
title Intraclass correlation associated with therapists: estimates and applications in planning psychotherapy research.
title_full Intraclass correlation associated with therapists: estimates and applications in planning psychotherapy research.
title_fullStr Intraclass correlation associated with therapists: estimates and applications in planning psychotherapy research.
title_full_unstemmed Intraclass correlation associated with therapists: estimates and applications in planning psychotherapy research.
title_short Intraclass correlation associated with therapists: estimates and applications in planning psychotherapy research.
title_sort intraclass correlation associated with therapists estimates and applications in planning psychotherapy research
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