IDEAS home Printed from https://ideas.repec.org/p/boc/usug12/16.html
   My bibliography  Save this paper

Handling interactions in Stata, especially with continuous predictors

Author

Listed:
  • Patrick Royston

    (MRC Clinical Trials Unit and University College London)

  • Willi Sauerbrei

    (University of Freiburg)

Abstract

In an era in which doctors and patients aspire to personalized medicine and more sophisticated risk estimation, detecting and modeling interactions between covariates or between covariates and treatment is increasingly important. In observational studies (for example, in epidemiology), interactions are known as effect modifiers; their presence can substantially change the understanding of how a risk factor impacts the outcome. However, modeling interactions in an appropriate and interpretable way is not straightforward. In our talk, we consider two related topics. The first topic is modeling interactions in observational studies that involve at least one continuous covariate, an area that practitioners apparently find difficult. We introduce a new Stata program, mfpigen, for detecting and modeling such interactions using fractional polynomials, adjusting for confounders if necessary. The second topic is modeling interactions between treatment and continuous covariates in randomized controlled trials. We outline a Stata program, mfpi, designed for this purpose. Key themes of our talk are the vital role played by graphical displays of interactions and the importance of applying simple plausibility checks.

Suggested Citation

  • Patrick Royston & Willi Sauerbrei, 2012. "Handling interactions in Stata, especially with continuous predictors," United Kingdom Stata Users' Group Meetings 2012 16, Stata Users Group.
  • Handle: RePEc:boc:usug12:16
    as

    Download full text from publisher

    File URL: http://repec.org/usug2012/UK12_royston.pdf
    Download Restriction: no

    Citations

    Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.
    as


    Cited by:

    1. Ashraf, Dawood & Rizwan, Muhammad Suhail & L’Huillier, Barbara, 2016. "A net stable funding ratio for Islamic banks and its impact on financial stability: An international investigation," Journal of Financial Stability, Elsevier, vol. 25(C), pages 47-57.

    More about this item

    NEP fields

    This paper has been announced in the following NEP Reports:

    Statistics

    Access and download statistics

    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:boc:usug12:16. See general information about how to correct material in RePEc.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Christopher F Baum). General contact details of provider: http://edirc.repec.org/data/stataea.html .

    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.

    We have no references for this item. You can help adding them by using 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.

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

    IDEAS is a RePEc service hosted by the Research Division of the Federal Reserve Bank of St. Louis . RePEc uses bibliographic data supplied by the respective publishers.