A researcher studying support for international institutions finds that Democrats are more likely to support such institutions than are Republicans. When she controls for income, she finds that individuals with higher incomes are about 12 points more supportive of international institutions regardless of party. This is an example of a(n) ______.
A) additive effect
B) spurious effect
C) interactive effect
D) zero-order effect

Question

Quizplus · Accepted Answer

This is an example of an additive effect since the effect of income on support for international institutions is independent of political party affiliation.

A Researcher Studying Support for International Institutions Finds That Democrats