How to calculate composite scores?

#1
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
 

JohnM

TS Contributor
#2
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).
 
#3
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?