# Is there a difference between an index score and a composite score?

Following on from my previous question on forming scale scores, my sample has 100 people who have answered 10 likert scale questions each on two academic subjects: Maths and English.

The likert scale is a 5 point scale, going from not important to absolute importance.

I have aggregated the scores:

• The maximum score a person can get is 40 (which is 10 responses x 4 which is the maximum score on the likert scale e.g. 4 = absolute importance).

• The minimum is 0 (which is 10 responses x 0 which is the minimum score on the likert scale e.g. 0 = not important)

If a person gets 20 points (total of 10 likert scale responses for Maths) and 30 points (total of 10 likert scale responses for English), my questions are:

1. Is 20 or 30 a composite score or an index score? (given that they are both based on subjective weighting aligned with the likert scale response)

2. Can I do a correlation analysis on the two scores? (given they are composite/index scores, hence represent a latent variable)

Many thanks

• I have merged your duplicate accounts. Because you have multiple questions, please register and use only that account. – whuber Aug 3 '11 at 14:16