How to Calculate Spearman Correlation
What is Spearman Correlation?
Spearman's rank correlation (rs) measures the strength of the monotonic relationship between two variables using their ranks. It is the non-parametric equivalent of Pearson's r and is more robust to outliers.
Step-by-Step Guide
- 1Rank each variable from 1 to n
- 2rs = 1 − (6Σd²) / (n(n²−1))
- 3d = difference in ranks for each pair
- 4Perfect rank agreement → rs=1; perfect reversal → rs=−1
Worked Examples
Input
Two raters rank 5 items: d² values: 1,0,4,1,0
Result
rs = 0.7 — moderate to strong rank correlation
1−6×6/(5×24)=0.7
Ready to calculate? Try the free Spearman Correlation Calculator
Try it yourself →