I have compiled a questionnaire consisting of items which aim to measure different aspects of elevator and staircase use. The main idea when composing the items was that it would be the most informative if I could measure the direction and the extent of influence the concept has on the individual. That is why items look like this:
"When I am in a hurry, I use the
staircase -3 - -2 - -1 - 0 - 1 - 2 - 3 elevator"
I have 70 items in total, which were constructed based on 15 categories, e.g. Laziness, Speed, etc. My plan was to just sum up the standardized values of items which I think belonged together to create scales to work with. I do not think an EFA approach would be applicable here, because I do not think there are any latent variables to define.
My question is: what would be the correct way to select the best items to include in the summed scales? Do you think my idea of summing the standardized item scores is correct, and if not, what would you do differently?
Edit: My main goal is to reduce the number of variables, and use them in a cluster analysis to explore if my sample could be divided into clusters in a meaningful way and if there are any nontrivial clusters. The research question is essentially: can people be categorized based on their luggage, how tired they are, etc. (these are the scales I am trying to create), and based on in which direction these "factors" influence their decisions.