How to calculate composite scores?

Hi everyone,

I know it's a bit embarassing to ask this question, but I hope someone can help :eek:

I conducted a survey using four different psychometric constructs. Each construct/scale consisted of 5 to 10 items using 4-point Likert scales. I would like to calculate
a) correlations between 2 or more scales
b) a dichotomous score based on construct A, that puts the survey participants into two different categories (by median-split?)
c) inter-group differences between these two groups for the other three scales (t-test?)

... and I'm really stuck on how to calculate the composite scores for each scale. Should I simply add response values for all scale items (probably not) or calculate the mean of all responses belonging to a scale, or do something else entirely?

Thx for helping in advance


TS Contributor
There's much more to this than simply adding together the scores from each scale. If it's a standard, published survey, it will have instructions on how to compute a composite score. If it's a survey you developed, you'll need to develop the theory behind it and through this research justify the method for computing the composite score (a ton of work).
Hi John,

thx for the quick reply. Of course, I used standard psychometric scales but information about composite scores was not provided for any of these.

Where can I learn more about the respective methods?