Vocabulary:
lurking vs. confounding
LURKING
VARIABLE
pA lurking variable is a variable that is not
among the explanatory or response variables in a study and yet may
influence the interpretation of relationships among those
variables.
CONFOUNDING
pTwo variables are confounded when their effects
on a response variable cannot be distinguished from each other.
The confounded variables may be either explanatory variables or
lurking variables.
But you often see them used interchangeably…