Correlation Resources: SPSS, R, Causality, Interpretation, and APA Style Reporting

This post provides links to a range of resources related to the use and interpretation of correlations. I wanted to provide a page with links to a number of additional resources that would be useful both for those of my students who might be keen to learn more and for anyone else who might be interested. Specifically, this post provides links to: (a) introductory book-style chapters on correlation, (b) resources related to assorted issues in correlation (i.e., discussion of causal inference, correlation with various variable types, range restriction, statistical power, correlation interpretation, and significance testing), (c) tutorials on computing correlations using SPSS and R, and (d) tips for reporting correlations in APA Style.

How to calculate confidence intervals of correlations with R

This post sets out how to calculate confidence intervals for correlations using R. Because I often get this question from people unfamiliar with R, it assumes no prior knowledge of R.

Canonical Correlation: Getting Started with R or SPSS

Canonical correlation is a method of modelling the relationship between two sets of variables. This post provides: (a) Examples of when canonical correlation can be useful; (b) Links to good online resources where you can learn about the technique; (c) Links to examples of running the analysis in R or SPSS; and (d) Examples of articles showing how to report a canonical correlation analysis.

Analysing ordinal variables

Ordinal variables create challenges for analysis. This post discusses: (a) definitions and distinctions related to ordinal variables, (b) theoretical issues related to ordinal variables, and (c) options for analysing ordinal variables.

Adjusting Correlations for Reliability | Attenuation Formula

This post discusses ways of adjusting correlations for reliability.

Tetrachoric Correlations | Overview and Resources

What do you do if you want to run a factor analysis on a set of binary variables?

Confidence Intervals and Correlations

In a previous post, I discussed the various scenarios for running significance tests on correlations.

A researcher recently asked me how to calculate confidence intervals for two correlations that share a common variable (i.e., dependent correlations).

Significance Tests on Correlations

OVERVIEW: I often speak to researchers wanting to compare the significance of two correlations. The two scenarios most commonly encountered are: 1) comparing dependent correlations; and 2) comparing independent correlations.

Formatting Correlation Matrices in Psychology

Researchers in psychology often want to present a correlation matrix of the main variables in a study. This post sets out one way of producing a formatted correlation matrix that conforms to APA style.

Using R to test for significant differences between two nonindependent correlations

I was recently asked about a quick and easy way to see whether the correlation between IV1 and DV is statistically significantly different from IV2 and DV. The follow post set out how this analysis can be conducted in R. The instructions assume that you have never used R before and are running Windows.