I can't thank the experts enough for their clarifications. One final question following my earlier posts on forming coomposite variables here, here, and here.

If I have measured some variables as cardinal numbers (e.g. 1, 2, 3, 4, 5 times) and others on a Likert scale, can I then just add the scores together?

For example:

1. How many times do you visit the local hospital per month? Answer: 5 times
2. How would you rate the medical service provided to you: Answer 3 on a scale of five going from poor to excellent.

Can I add 5 and 3 and say the composite score is 8?

What if the likert scale goes from negative to positive (e.g. strongly disagree = -2, disagree = -1, neither disagree or agree = 0, agree = 1 and strong agree = 2)?

Would the same rule as above apply if the score is say 0 or -2?

My objective is to keep the aggregation process simple and not get 'confused' in complex statistical formulas.