IDEAS home Printed from https://ideas.repec.org/a/sae/evarev/v36y2012i6p430-448.html
   My bibliography  Save this article

Increasing the Degrees of Freedom in Future Group Randomized Trials

Author

Listed:
  • David M. Murray
  • Jonathan L. Blitstein
  • Peter J. Hannan
  • William R. Shadish

Abstract

Background: This article revisits an article published in Evaluation Review in 2005 on sample size estimation and power analysis for group-randomized trials. With help from a careful reader, we learned of an important error in the spreadsheet used to perform the calculations and generate the results presented in that article. As we studied the spreadsheet, we discovered other minor errors. When we corrected the errors, we found that the results were substantially different and that the conclusions reported in the original article were not always appropriate. Objective: This article corrects the errors and reports the results as they should have been reported originally. Method: Using a random-effects meta-analytic model, estimates of intraclass correlation were combined from two studies to guide sample size calculations for a new study. Results: The df * method can result in improved power or smaller studies when used a priori to plan future group-randomized trials, though the improvements will be modest in larger studies and will likely be insufficient to provide adequate power to small studies. Conclusion: Smaller group-randomized trials are often desirable, for example, as pilot studies to help plan for a full-scale efficacy trial, as replication studies, or in situations in which resource constraints prohibit a larger trial. We discuss the circumstances under which the df * method will be most helpful and the risks associated with conducting smaller studies.

Suggested Citation

  • David M. Murray & Jonathan L. Blitstein & Peter J. Hannan & William R. Shadish, 2012. "Increasing the Degrees of Freedom in Future Group Randomized Trials," Evaluation Review, , vol. 36(6), pages 430-448, December.
    • Handle: RePEc:sae:evarev:v:36:y:2012:i:6:p:430-448
    DOI: 10.1177/0193841X13480147
    as

    Download full text from publisher

    File URL: https://journals.sagepub.com/doi/10.1177/0193841X13480147
    Download Restriction: no
    File URL: https://libkey.io/10.1177/0193841X13480147?utm_source=ideas
    LibKey link: if access is restricted and if your library uses this service, LibKey will redirect you to where you can use your library subscription to access this item
    ---><---

    References listed on IDEAS

    as
    1. Forster, J.L. & Murray, D.M. & Wolfson, M. & Blaine, T.M. & Wagenaar, A.C. & Hennrikus, D.J., 1998. "The effects of community policies to reduce youth access to tobacco," American Journal of Public Health, American Public Health Association, vol. 88(8), pages 1193-1198.
    2. Sorensen, G. & Barbeau, E. & Stoddard, A.M. & Hunt, M.K. & Kaphingst, K. & Wallace, L., 2005. "Promoting behavior change among working-class, multiethnic workers: Results of the healthy directions - Small business study," American Journal of Public Health, American Public Health Association, vol. 95(8), pages 1389-1395.
    Full references (including those not matched with items on IDEAS)

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Jonathan L. Blitstein & David M. Murray & Peter J. Hannan & William R. Shadish, 2005. "Increasing the Degrees of Freedom in Future Group Randomized Trials," Evaluation Review, , vol. 29(3), pages 268-286, June.
    2. Kontos, Emily Z. & Emmons, Karen M. & Puleo, Elaine & Viswanath, K., 2011. "Determinants and beliefs of health information mavens among a lower-socioeconomic position and minority population," Social Science & Medicine, Elsevier, vol. 73(1), pages 22-32, July.
    3. Jonathan L. Blitstein & Peter J. Hannan & David M. Murray & William R. Shadish, 2005. "Increasing the Degrees of Freedom in Existing Group Randomized Trials," Evaluation Review, , vol. 29(3), pages 241-267, June.
    4. Simona Buscemi & Antonella Plaia, 2020. "Model selection in linear mixed-effect models," AStA Advances in Statistical Analysis, Springer;German Statistical Society, vol. 104(4), pages 529-575, December.
    5. Mark Wolfson & Heather Champion & Todd Rogers & Rebecca H. Neiberg & Dianne C. Barker & Jennifer W. Talton & Edward H. Ip & Ralph B. D'Agostino Jr & Maria T. Parries & Doug Easterling, 2011. "Evaluation of Free to Grow: Head Start Partnerships to Promote Substance-Free Communities," Evaluation Review, , vol. 35(2), pages 153-188, April.
    6. Gautam, Jeny & Glover, Marewa & Scragg, Robert & Bullen, Chris & Gentles, Dudley & Nosa, Vili & McCool, Judith, 2014. "Parental and retail supply of tobacco to minors: Findings from a community-based social supply intervention study," Health Policy, Elsevier, vol. 117(1), pages 120-127.
    7. Hana Ross & Frank J. Chaloupka, 2003. "The effect of cigarette prices on youth smoking," Health Economics, John Wiley & Sons, Ltd., vol. 12(3), pages 217-230, March.
    8. Dixon, Marlene A., 2009. "From Their Perspective: A Qualitative Examination of Physical Activity and Sport Programming for Working Mothers," Sport Management Review, Elsevier, vol. 12(1), pages 34-48, February.
    9. Mohammad Nurul Azam & Mohammad Shahjahan & Mahbuba Yeasmin & Nasar U Ahmed, 2016. "Prevalence of Smokeless Tobacco among Low Socioeconomic Populations: A Cross-Sectional Analysis," PLOS ONE, Public Library of Science, vol. 11(6), pages 1-13, June.
    10. Wakefield, Melanie A PhD & Chaloupka, Frank J. PhD, 1999. "Effectiveness of Comprehensive Tobacco Control Programs in Reducing Teenage Smoking: A Review," University of California at San Francisco, Center for Tobacco Control Research and Education qt46n6b9mv, Center for Tobacco Control Research and Education, UC San Francisco.
    11. Devine, Carol M. & Jastran, Margaret & Jabs, Jennifer & Wethington, Elaine & Farell, Tracy J. & Bisogni, Carole A., 2006. ""A lot of sacrifices:" Work-family spillover and the food choice coping strategies of low-wage employed parents," Social Science & Medicine, Elsevier, vol. 63(10), pages 2591-2603, November.
    12. Levy, David T. & Hyland, Andrew & Higbee, Cheryl & Remer, Lillian & Compton, Christine, 2007. "The role of public policies in reducing smoking prevalence in California: Results from the California Tobacco Policy Simulation Model," Health Policy, Elsevier, vol. 82(2), pages 167-185, July.
    13. Arthur, Michael W. & Briney, John S. & Hawkins, J. David & Abbott, Robert D. & Brooke-Weiss, Blair L. & Catalano, Richard F., 2007. "Measuring risk and protection in communities using the Communities That Care Youth Survey," Evaluation and Program Planning, Elsevier, vol. 30(2), pages 197-211, May.
    14. Glorian Sorensen & Eve M Nagler & Pratibha Pawar & Prakash C Gupta & Mangesh S Pednekar & Gregory R Wagner, 2017. "Lost in translation: The challenge of adapting integrated approaches for worker health and safety for low- and middle-income countries," PLOS ONE, Public Library of Science, vol. 12(8), pages 1-25, August.
    15. Nelson, Candace C. & Sapp, Amy & Berkman, Lisa F. & Li, Yi & Sorensen, Glorian, 2011. "Allocation of household responsibilities influences change in dietary behavior," Social Science & Medicine, Elsevier, vol. 73(10), pages 1517-1524.
    16. Louisa Ming Yan Chung & Joanne Wai Yee Chung & Albert P. C. Chan, 2019. "Building Healthy Eating Knowledge and Behavior: An Evaluation of Nutrition Education in a Skill Training Course for Construction Apprentices," IJERPH, MDPI, vol. 16(23), pages 1-14, December.
    17. Jason, Leonard A. & Pokorny, Steven B. & Adams, Monica, 2008. "A randomized trial evaluating tobacco possession-use-purchase laws in the USA," Social Science & Medicine, Elsevier, vol. 67(11), pages 1700-1707, December.
    18. Kristin Feltmann & Johanna Gripenberg & Tobias H. Elgán, 2022. "Compliance Checks Decrease Cigarette Sales Rates to Pseudo-Underaged Mystery Shoppers: A Quasi-Experimental Control Group Study," IJERPH, MDPI, vol. 19(20), pages 1-13, October.

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:sae:evarev:v:36:y:2012:i:6:p:430-448. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: SAGE Publications (email available below). General contact details of provider: .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.