t-test for Difference in Difference significance

[Lukas Oswald]

Hi Statalists,

I am currently working on the below depicted table, where I display the results of univariate t-tests for the different groups and over different points in time.

I was able to calculate t tests and statistical differences for all but the Diff vs. Diff section marked with an "x"

Category/Year	1	2	3	Diff 1-2	Diff 1-3
(1) Group A	✓	✓	✓	✓	✓
(2) Group B	✓	✓	✓	✓	✓
Diff (1) vs. (2)	✓	✓	✓	x	x

I work with panel data (id, year) and I have indicators (0/1) to which group the respective id belongs.

So far I have tried various options but was not able to solve it.

Thanks in advance for ideas on how to approach this.

Best
Lukas

[George Ford]

You need to provide more detail to get an answer. How are you computing the DID?