Instrumental Variable Analyses for Observational Comparative Effectiveness Research: The Paired Availability Design
Authors: Stuart G. Baker, Karen S. Lindeman
Journal: Annals of Internal Medicine (2014)

Letters2 December 2014Instrumental Variable Analyses for Observational Comparative Effectiveness Research: The Paired Availability DesignStuart G. Baker, ScD and Karen S. Lindeman, MDStuart G. Baker, ScDFrom National Institutes of Health, Bethesda, Maryland, and Johns Hopkins Medicine, Baltimore, Maryland.Search for more papers by this author and Karen S. Lindeman, MDFrom National Institutes of Health, Bethesda, Maryland, and Johns Hopkins Medicine, Baltimore, Maryland.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/L14-5029 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail TO THE EDITOR:Garabedian and colleagues' article (1) discusses potential bias in the instrumental variable analysis of observational studies. However, it did not mention an important type of instrumental variable approach for use with observational data, namely, the paired availability design (PAD) (2–4). Under the PAD, time period is the instrumental variable and the availability of new treatment for patients changes over time periods.The PAD makes a key assumption that Garabedian and colleagues discuss: that the instrument affects the outcome only through treatment. The PAD also assumes stable preferences, namely, that treatment preferences do not change over time. For ...References1. Garabedian LF, Chu P, Toh S, Zaslavsky AM, Soumerai SB. Potential bias of instrumental variable analyses for observational comparative effectiveness research. Ann Intern Med. 2014;161:131-8. [PMID: 25023252] doi:10.7326/M13-1887 LinkGoogle Scholar2. Baker SG, Lindeman KS. The paired availability design: a proposal for evaluating epidural analgesia during labor. Stat Med. 1994;13:2269-78. [PMID: 7846425] CrossrefMedlineGoogle Scholar3. Baker SG, Lindeman KS, Kramer BS. The paired availability design for historical controls. BMC Med Res Methodol. 2001;1:9. [PMID: 11602018] CrossrefMedlineGoogle Scholar4. Baker SG, Lindeman KS. Revisiting a discrepant result: a propensity score analysis, the paired availability design for historical controls, and a meta-analysis of randomized trials. J Causal Inference. 2013;1:51-82. CrossrefGoogle Scholar Author, Article, and Disclosure InformationAffiliations: From National Institutes of Health, Bethesda, Maryland, and Johns Hopkins Medicine, Baltimore, Maryland.Disclosures: Authors have disclosed no conflicts of interest. Forms can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=L14-0460. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetailsSee AlsoPotential Bias of Instrumental Variable Analyses for Observational Comparative Effectiveness Research Laura Faden Garabedian , Paula Chu , Sengwee Toh , Alan M. Zaslavsky , and Stephen B. Soumerai Potential Bias of Instrumental Variable Analyses for Observational Comparative Effectiveness Research Laura Faden Garabedian , Paula Chu , Sengwee Toh , Alan M. Zaslavsky , and Stephen B. Soumerai Instrumental Variable Analyses for Observational Comparative Effectiveness Research: The Paired Availability Design Laura Faden Garabedian , Alan M. Zaslavsky , and Stephen B. Soumerai Instrumental Variable Analyses for Observational Comparative Effectiveness Research: The Paired Availability Design Laura Faden Garabedian , Alan M. Zaslavsky , and Stephen B. Soumerai Metrics Cited byLatent class instrumental variables: a clinical and biostatistical perspective 2 December 2014Volume 161, Issue 11Page: 840-841KeywordsAnalgesiaComparative effectiveness researchConflicts of interestDisclosureInstrumental variable analysisObservational studiesPatients ePublished: 2 December 2014 Issue Published: 2 December 2014 Copyright & PermissionsCopyright © 2014 by American College of Physicians. All Rights Reserved.PDF downloadLoading ...