What is the difference between a part correlation and a partial correlation in terms of what they control for?

• A. Part correlation is another name for a semi-partial correlation.
• B. Partial correlation measures the relationship between two variables while controlling for one or more additional variables.
• C. Both concepts describe the exact same relationship and control the same variables.
• D. Neither concept involves controlling for other variables in the relationship.

Answer: (B)

The idea being tested is how removing the influence of other variables changes the observed relationship between two variables. A partial correlation removes the effects of the control variables from both of the variables before assessing their relationship, so you’re looking at the association that is not explained by those controls. A part (semi-partial) correlation, in contrast, removes the effects of the controls from only one of the variables (usually the predictor) before correlating with the other variable, highlighting the unique contribution of that variable after accounting for the controls in that one variable. So the key difference is what is being held constant: partial correlation holds the control variables constant in both variables, while part correlation does this for only one variable.