Ordinal Predictors in Regression Analysis
Companion webpage to the YouTube video tutorial
Arndt Regorz, Dipl. Kfm. & M.Sc. Psychologie, 05/25/2021
This video shows you different approaches for dealing with an ordinal predictor in a regression analysis. Furthermore, here you can find the full sources for my video.
Content
1. Video tutorial
(Note: When you click on this video you are using a service offered by YouTube.)
2. Sources for the video
Walter et al., 1987
Staircase coding of ordinal predictor with several binary variables:
Walter, S. D., Feinstein, A. R., & Wells, C. K. (1987). Coding ordinal independent variables in multiple regression analyses.
American Journal of Epidemiology, 125(2), 319-323.
https://doi.org/10.1093/oxfordjournals.aje.a114532
Labovitz, 1970
Arguing for treating ordinal predictors as on an interval scale:
Labovitz, S. (1970). The assignment of numbers to rank order categories. American Sociological Review, 35(3), 515-524.
https://doi.org/10.2307/2092993
Mayer, 1971
Arguing against treating ordinal predictors as on an interval scale:
Mayer, L. S. (1971). A note on treating ordinal data as interval data. American Sociological Review, 36(3), 519-520.
https://doi.org/10.2307/2093098
Williams, 2020
Using mid-points of ordinal categories & testing, whether ordinal scale can be treated as interval:
Williams, R. (2020). Ordinal independent variables. University of Notre Dame.
https://www3.nd.edu/~rwilliam/stats3/OrdinalIndependent.pdf
Brown, 2011
Overview over discussion about Likert items and Likert scales with additional sources:
Brown, J. D. (2011). Likert items and scales of measurement. Statistics, 15(1), 10-14.
https://hosted.jalt.org/test/bro_34.htm
Wu & Leung, 2017
Recommendation for a 11-point scale (0 to 10) when using a single-item Likert scale:
Wu, H., & Leung, S. O. (2017). Can likert scales be treated as interval scales?—A simulation study. Journal of Social Service Research, 43(4), 527-532.
https://doi.org/10.1080/01488376.2017.1329775
Gertheiss & Tutz, 2009
Advanced method: Penalized regression with ordinal predictors:
Gertheiss, J., & Tutz, G. (2009). Penalized regression with ordinal predictors. International Statistical Review, 77(3), 345-365. https://doi.org/10.1111/j.1751-5823.2009.00088.x
Implementation of this method in R:
Gertheiss, J., Hoshiyar, A., & Scheipl, F. (2021). Package 'ordPens' [Reference manual]. CRAN. https://cran.r-project.org/web/packages/ordPens/ordPens.pdf
Gertheiss, J., Scheipl, F., Lauer, T., & Ehrhardt, H. (2022). Statistical inference for ordinal predictors in generalized additive models with application to Bronchopulmonary Dysplasia. BMC Research Notes, 15(1), 1-6. https://doi.org/10.1186/s13104-022-05995-4
Helwig, 2017
Advanced method: Ordinal smoothing splines:
Helwig, N. E. (2017). Regression with ordered predictors via ordinal smoothing splines. Frontiers in Applied Mathematics and Statistics, 3, 15. https://doi.org/10.3389/fams.2017.00015