I am doing a research that consists of five variables. I have adopted the research instrument of different five previous studies for these five constructs;
1) IV is measured with 7point likert scale(adopted)
2)DV is measured with 5 point likert scale (adopted)
3) Mediating variable measured with 7 point likert scale (adopted)
4) moderating variable 1 measured with 6 point likert scale
5) moderating variable 2 measured with 7 point likert scale.
Please guide, before going for data collection and statistical techniques, may I use these adopted scale "as it is with no transformation in likert scales" or I have to transform the likert scales to generate uniformity for respondents. If transformation is necessary, please suggest some reading of how to do it.