Correlate scales from different sources when data is in long format

[Jen Walker]

Hi

My data is in long format and consists of six sub-scales (Scale1-Scale6) and three different respondents (parent, teacher, and child).
My aim is to test the correlation between the child responses and the teacher / parent responses for each sub-scale (12 correlations in total). For example;

1. Correlate parent and child responses for Scale 1
2. Correlate teacher and child responses for Scale 1
3. Correlate parent and child responses for Scale 2
4. Correlate teacher and child responses for Scale 2
5. Correlate parent and child responses for Scale 3
6. Correlate teacher and child responses for Scale 3

.
.
Etc.

When using the by respondent prefix (by Respondent, sort: correlate Scale1-Scale6) the results show the correlation of Scale1-Scale6 by respondent. Alternatively, when I select only one Scale (by Respondent, sort: correlate Scale1) the results equal 1 for each respondent.

I appreciate I can rename the variables to distinguish the respondent, convert the dataset to wide format then correlate but my preference is to keep the dataset long if possible.

I am currently using Stata version 15.1.

Thanks in advance for your time.