Statistical Tests and Models

What tests are good to see if independent observations are correlated?

Relative Risks, Chi-square test, logistic regression

What tests are good to see if correlated observations are correlated?

McNemar’s chi-square test, conditional logistic regression, GEE modeling

What are the alternatives to the chi-square test if there are sparse cells?

Fisher’s exact test, McNemar’s exact test

Chi-square test

compares proportion between groups with independent observations

McNemar’s Chi-square

for correlated data

What chi-square tests are for independent data?

Mantel Haenzel, Pearsons

Logistic regression

multivariate technique, independent data

conditional logistic regression

multivariate technique, correlated data (matched)

generalized estimating equations (GEE)

for repeated measures, correlated data

Simple Linear Regression

• assessing association between two continuous variables

• uses Least Square Method

• gives regression coefficients

Multiple Linear Regression

• gives linear association between a continuous outcome after the adjustment of covariates

• predictor variables can be categorical or continuous

  • uses Maximum Likelihood estimate

Logistic Regression

• looks at assoication between exposure and birnar outcome after adjusting for covariates

• based on max likihood method

• used in case control and cross-sectional studies

• can be used in cohort studies but assumes complete follow-up

  • log(odds); OR= e^b1

Cox Proportional Hazards Model

• follows proportional hazards assumption

• uses time-to-event data (person-time)

• used in cohort studies

• log(h(t/x')/(ho(t)

• use for survival analysis

• gives hazard ratio (HR)

Possion Regression

• use for person-time

  • gives RR (log(Rate))

matched case-control

use conditional logistic regression (analogous to logistic model)

nested case-control studies

use conditional logistic regression

• matching var is length of followup

• analogous to cox regression

case-cohort study

use cox regression

• handles possibility that control becomes case