11. Some Alternatives to Traditional ANCOVA

  1. Andrew Rutherford

Published Online: 30 SEP 2013

DOI: 10.1002/9781118491683.ch11

Anova and Ancova, Second Edition

Anova and Ancova, Second Edition

How to Cite

Rutherford, A. (2011) Some Alternatives to Traditional ANCOVA, in Anova and Ancova, Second Edition, John Wiley & Sons, Inc., Hoboken, New Jersey. doi: 10.1002/9781118491683.ch11

Publication History

  1. Published Online: 30 SEP 2013
  2. Published Print: 7 OCT 2011

ISBN Information

Print ISBN: 9780470385555

Online ISBN: 9781118491683



  • covariate;
  • general linear models (GLMs);
  • heterogeneous regression;
  • multicolinearity;
  • traditional ANCOVA


This chapter focuses on heterogeneous ANCOVA general linear models (GLMs), and discusses two further alternatives to traditional ANCOVA and the ability of heterogeneous regression ANCOVA to ameliorate the problems caused by a relationship between the covariate(s) and the experimental conditions. The basic problem posed by heterogeneous regression ANCOVA is that experimental effects vary as a function of the covariate. Applying traditional ANCOVA when a relationship exists between the covariate and the experimental conditions will provide an analysis which is statistically correct, but it is unlikely to apply easily or usefully to the real world. By avoiding covariate distribution conflation, the relation between the experimental conditions and the covariate in heterogeneous regression ANCOVA changes from a condition that seriously complicated the interpretation of adjusted experimental effects and questioned the real world validity of the analysis, to the familiar regression topic of multicolinearity.

Controlled Vocabulary Terms

analysis of covariance; covariate; regression