Professor Swanson Developed an Index of Marital Happiness

Multiple Choice

Professor Swanson developed an index of marital happiness. Several items in Swanson's questionnaire were not a part of the index (i.e., "How many serious quarrels or arguments have you had with your spouse in the past year?") . Swanson compared the index scores of marital happiness with these questions. Swanson was doing:

A) index construction.
B) item analysis.
C) external validation.
D) analysis invalidation.
E) Likert scaling.