Conditional logistic regression: Difference between revisions

Content deleted Content added
m v2.04 - Repaired 1 link to disambiguation page - (You can help) - Nick Day / Fix errors for CW project (Title linked in text)
Line 1:
'''Conditional logistic regression''' is an extension of [[logistic regression]] that allows one to take into account [[stratification (clinical trials)|stratification]] and [[Matching (statistics)|matching]]. Its main field of application is [[observational studies]] and in particular [[epidemiology]]. It was devised in 1978 by [[Norman Breslow]], [[Nick Day (statistician)|Nicholas Day]], [[Katherine Halvorsen]], [[Ross L. Prentice]] and C. Sabai.<ref name="pmid727199">{{cite journal|vauthors=Breslow NE, Day NE, Halvorsen KT, Prentice RL, Sabai C| title=Estimation of multiple relative risk functions in matched case-control studies. | journal=Am J Epidemiol | year= 1978 | volume= 108 | issue= 4 | pages= 299–307 | pmid=727199 | doi= 10.1093/oxfordjournals.aje.a112623| url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=727199 }} </ref> It is the most flexible and general procedure for matched data.
 
==Motivation==
Observational studies use [[stratification (clinical trials)|stratification]] or [[Matching (statistics)|matching]] as a way to control for [[confounding]]. Several tests existed before conditional logistic regression for matched data as shown in [[Conditional logistic regression#Related tests|related tests]]. However, they did not allow for the analysis of continuous predictors with arbitrary stratum size. All of those procedures also lack the flexibility of conditional logistic regression and in particular the possibility to control for covariates.
 
Logistic regression can take into account stratification by having a different constant term for each stratum. Let us denote <math>Y_{i\ell}\in\{0,1\}</math> the label (e.g. case status) of the <math>\ell</math>th observation of the <math>i</math>th stratum and <math>X_{i\ell}\in\mathbb{R}^p</math> the values of the corresponding predictors. Then, the likelihood of one observation is