topic Re: Code for Single Interrupted Time Series graphic display? in New SAS User

Code for Single Interrupted Time Series graphic display?

cmc_NYC — Tue, 11 Jan 2022 00:05:45 GMT

Hello all,

I have developed a model to test the impact of a 2017 event on distress in a population and it was run by a research center using data to which I don't have access. I'm having trouble finding sample code for using this output to create a display like this. I'm now working with the output and trying to display the coefficients in a graphic that looks something like this. (This is from Warton et al 2020) For this particular display I would just have one line not two.

I have two kinds of output that seem relevant:

1) The mean distress score for the group each year from 2011 to 2018. Here's my first pass at that program, that shows those scores. This did not work. In particular, I'm not seeing how to create the vertical line indicating the event in 2017

Data AimII_Table2;
input TimeElapsed Time Distress Event $;
datalines;
0 2011 3.7339771 Before
1 2012 3.8688698 Before
2 2013 3.8669976 Before
3 2014 3.5876379 Before
4 2015 3.64495 Before
5 2016 3.4850532 Before
6 2017 3.6610487 After
7 2018 3.5467001 After
;

2) The coefficients for the univariate regression, so coefficients for time, before and after the event, and the interaction terms for time*after the event

Estimated Regression Coefficients
Parameter	Estimate	Standard Error	t Value	Pr > \|t\|
Intercept	3.8593132	0.06640163	58.12	<.0001
TimeElapsed	-0.0644708	0.02134668	-3.02	0.0025
AfterEvent After Event	0.4878268	0.84369762	0.58	0.5631
AfterEvent Before Event	0.0000000	0.00000000	.	.
TimeElapsed*AfterEvent After Event	-0.0498778	0.13118431	-0.38	0.7038
TimeElapsed*AfterEvent Before Event	0.0000000	0.00000000	.	.

Thank you for any ideas!

Re: Code for Single Interrupted Time Series graphic display?

cmc_NYC — Tue, 11 Jan 2022 00:09:08 GMT

Sorry, with the mean distress levels by year I used this code following the data lines above.

Proc sgplot data=AimII_Table2;
scatter x=Time y=Distress;
series x=Time y=Distress;
reg x=Time y=Distress/group=Election;
refline
run;

Re: Code for Single Interrupted Time Series graphic display?

Reeza — Tue, 11 Jan 2022 00:15:41 GMT

You need to add a value for where you want the refline and specify the axis.

refline 2017 / axis=x label='Event 2017';

Ref Lines examples:
https://documentation.sas.com/doc/en/pgmsascdc/9.4_3.5/grstatproc/n19gxtzyuf79t3n16g5v26b73ckv.htm#n1vl5u624cjn05n1xvpnhei9b8s4

Re: Code for Single Interrupted Time Series graphic display?

cmc_NYC — Tue, 11 Jan 2022 15:33:28 GMT

Thank you. I had lots of examples of REFLINE code, but just needed something that broke down how that worked.