Programming the statistical procedures from SAS

SAS/STAT procedure to calculate before and after performance analysis?

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Occasional Contributor
Posts: 12

SAS/STAT procedure to calculate before and after performance analysis?

I want to know the procedure(s) which will best compare and contrast the the performance of an event before and after implementation of new policy or after certain date?

For example: In a industry they have implemented new policy, so they wanted to compare the effectiveness of the policy, by comparing the before and after performance for one year, since the policy was implemented, they would like to compare the outcome (Percent, significance testing) based upon certain event?

Please let me know what procedures will help in doing these type of  analysis?

Super User
Posts: 18,528

Re: SAS/STAT procedure to calculate before and after performance analysis?

Do you have a control group to test against? How can attribute changes to implementation versus other factors?

You haven't provided enough information but it sounds like a basic ANOVA or even t-test procedure.

Occasional Contributor
Posts: 12

Re: SAS/STAT procedure to calculate before and after performance analysis?

Thanks for the reply. Actually My data is the from the meet industry where they perform sampling for few pathogens, so to prevent food borne disease they have implemented new inspection procedures for the industry. so now they have to compare the rates of positive counts of pathogens, their significance testing using certain model and volume weighted positive rates (depends on the amount of meet produced in that industry) before and after the implementation of the inspection for a certain period of time may be  months, or quarter or bi-yearly, yearly and so on. so now they wanted to calculate this comparison in one procedure. I wanted one procedure which could do it.? if you have worked on this type of scenarios, please do help me?

Super User
Posts: 18,528

Re: SAS/STAT procedure to calculate before and after performance analysis?

You may want to control for different plants, meats, etc so you may going into proc panel or mixed here.

SAS Employee
Posts: 240

Re: SAS/STAT procedure to calculate before and after performance analysis?

Rates are typically modeled using Poisson or negative binomial regression.  This can be done in PROC GENMOD.  See the discussion and example in this note.

SAS Employee
Posts: 89

Re: SAS/STAT procedure to calculate before and after performance analysis?

I am not sure you have access to the SAS/ETS tools but this is exactly what PROC PANEL is built for.  Here is a link to the documentation SAS/ETS(R) 13.2 User's Guide

It certainly is possible to do this with something like PROC MIXED but it would take quite a bit more coding to accomplish. 

Respected Advisor
Posts: 2,655

Re: SAS/STAT procedure to calculate before and after performance analysis?

And if it is a very simple before/after comparison on a single variable, PROC TTEST may be all that is needed.

Steve Denham

Super User
Posts: 18,528

Re: SAS/STAT procedure to calculate before and after performance analysis?

If it's counts it may also be a chi-square test...

Occasional Contributor
Posts: 12

Re: SAS/STAT procedure to calculate before and after performance analysis?

I used proc mixed, it gives the output more similar to the required output. Thanks to everyone for the reply and help.

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