Hello,

I am writing a descriptive paper on substance use estimates across 4 years (2013-2017) using a longitudinal data.

I initially calculated the point estimates (prevalence) for each year and compared the confidence interval overlap from 2013 and 2017 to suggest significance. Now, I'm getting push back from colleagues suggesting I should do a real test for trend rather than comparing CIs. While this makes sense, I'm not sure what test to carry out since I assume lincom works best for cross-sectional data. Also, since I did not conduct a regression, I am unable to carry out the other xt..tests that are normally used to test time differences in panel data. Also, since I have so much data, I considered using lincom only for estimates that were 'significant' when I used the confidence overlap test, but I was informed that seemed like cherry-picking.

Can I use lincom to test for differences between 2013 and 2017 estimates using longitudinal data or is there any other test you suggest that I can use?

Thank you