Hi everyone
I have conducted a DiD-analysis and want to plot trend graphs of the dependent variable for the intervention and control group. The main point is to visualize the trends to assess the common trend assumption (also know as parallell paths assumption). Briefly,
It is commonly visualized with a graph like this:

Where the dotted line is not necessary and only included in the picture to illustrate the trend for units receiving treatment if they had not received treatment.
However, I am unsure how to get a correct graph in Stata and I wonder if anyone can give me any leads on this?
The dependent variable is monthly regional suicide rate and the treatment status variable is aggregated regions where the intervention group consist of four regions and the control group consist of two regions. Here is some info about my data set:
And I will also cross-refer to a related thread: https://www.statalist.org/forums/for...regional-units
I have conducted a DiD-analysis and want to plot trend graphs of the dependent variable for the intervention and control group. The main point is to visualize the trends to assess the common trend assumption (also know as parallell paths assumption). Briefly,
The key assumption here is what is known as the “Parallel Paths” assumption, which posits that the average change in the comparison group represents the counterfactual change in the treatment group if there were no treatment
Where the dotted line is not necessary and only included in the picture to illustrate the trend for units receiving treatment if they had not received treatment.
However, I am unsure how to get a correct graph in Stata and I wonder if anyone can give me any leads on this?
The dependent variable is monthly regional suicide rate and the treatment status variable is aggregated regions where the intervention group consist of four regions and the control group consist of two regions. Here is some info about my data set:
Code:
. xtdescribe region: 1, 2, ..., 6 n = 6 bymonth: 0, 1, ..., 71 T = 72 Delta(bymonth) = 1 unit Span(bymonth) = 72 periods (region*bymonth uniquely identifies each observation) Distribution of T_i: min 5% 25% 50% 75% 95% max 72 72 72 72 72 72 72 Freq. Percent Cum. | Pattern ---------------------------+-------------------------------------------------------------------------- 6 100.00 100.00 | 111111111111111111111111111111111111111111111111111111111111111111111111 ---------------------------+-------------------------------------------------------------------------- 6 100.00 | XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX . list suiciderate bymonth eventdate region treated_region in 1/10 +----------------------------------------------------------------------+ | suicid~e bymonth eventdate region treate~n | |----------------------------------------------------------------------| 1. | .3552352 0 January2012 North central region Control | 2. | .4736469 1 February2012 North central region Control | 3. | 2.012999 2 March2012 North central region Control | 4. | 2.486646 3 April2012 North central region Control | 5. | 1.420941 4 May2012 North central region Control | |----------------------------------------------------------------------| 6. | 1.302529 5 June2012 North central region Control | 7. | 1.657764 6 July2012 North central region Control | 8. | 2.012999 7 August2012 North central region Control | 9. | 1.420941 8 September2012 North central region Control | 10. | .9472938 9 October2012 North central region Control | +----------------------------------------------------------------------+
And I will also cross-refer to a related thread: https://www.statalist.org/forums/for...regional-units
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