Correlation Coefficient (r)

Strength of association between different ratings of the same thing

Authors

Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Correlation coefficient (r) reflects the Direction and magnitude of linear association between variables

Limitations:

• Only gives info on How closely associated the numbers are (if one increases or decreases, the other does as well)
• Does NOT give info on how well those actual values agree (level of agreement?)

Scoring

Interpretation

Direction (regardless of magnitude):

• Positive correlation (+r): as one variable increases, the other variable increases
• Negative correlation (‐r): as one variable increases, the other variable decreases
  • AKA inverse correlation

Magnitude (regardless of direction):

• 18. values range from: 0.00 (no association) to 1.00 (perfect association)
• The closer (r) is to 1.00, the stronger the association between variables