I am working on a survey analysis looking at the effect of an intervention with three components (each having multiple sub-parts). Questions ask respondents how frequently they used each component. Two of the questions have scales ranging from 1 to 5 (never/rarely/often/almost always/always), while the other question has a scale ranging from 1 to 4 (never/1-2 times/3-4 times/5 or more times).
Here are my questions:
Is it okay to sum all three questions together despite being on different scales? If not, how should I remedy the scale differences given that they are all measuring the same underlying construct (how the overall intervention was adopted)?
Each question has a different number of sub-parts (Q1 has 4, Q2 has 5, and Q3 has 6) b/c the number of items in each part of the intervention varies. Therefore, since the answer scale of Q1 is 1 to 5 and it has 4 sub-parts, the theoretical sum for any respondent could range from 4 (lowest) to 20 (highest), but for Q2, the range is obviously different (5 to 25). Q3 is on a different range (6 to 24) because the answer scale range is 1 to 4 and it has 6 sub-parts. How can I standardize the ranges? Do I even need to?
I hope these questions make sense and thanks in advance for any help! It is greatly appreciated!