Correlation
Statistics & analysis
Definition
A measure of how strongly two variables move together, from −1 to +1 — Pearson's r for continuous linear relationships, Spearman's rho for ordinal or non-normal data.
Correlation quantifies association, not causation: r = 0.6 between stress and turnover intention says the two travel together, not that one causes the other. Direction, strength and significance are three separate pieces of information — report all three.
Rules of thumb treat |r| around 0.1 as small, 0.3 as medium and 0.5 as large, but interpretation is field-dependent. Always inspect the scatterplot: outliers and non-linearity can manufacture or mask correlations.
Where it's used
- Preliminary relationship screening before regression
- Convergent validity evidence between related scales
Software used
SPSSRPythonJASP
Guides that use this concept
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