Single group comparison of incidence pre and post

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Regular Contributor
Posts: 163

Single group comparison of incidence pre and post

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I have a single group with incidence pre and post some intervention. The populations are different pre and post but I am not sure how to account for this in my analysis.

Super User
Posts: 13,583

Re: Single group comparison of incidence pre and post

What type of analysis are you actually attempting - research question to answer?

And some example data might help, replace anything sensitive with different values like xxxx, yyyy or similar.

 

Regular Contributor
Posts: 163

Re: Single group comparison of incidence pre and post

Research question is: is the intervention effective in reducing the number of injuries?

 

I have data from 5 different counties, with the populations pre-intervention and post-intervention, along with the incidence of injuries pre and post intervention as well.

Super User
Posts: 13,583

Re: Single group comparison of incidence pre and post

Do you want to know about each county or the data overall?

Is the population in the same data set as the incidence rate?

Do you have a variable that indicates whether a value is pre or post?

 

If you had posted some example data these questions would not be needed.

 

McNemar's test is sort of designed or a 2x2 table. is your data in form conducive to that? That would tend to look like

When  value

 

Pre      count yes

pre       count no

Post    Count yes

Post    count no

 

Also there are number of procedures that will do that test, or similar? Which one have you mind?

 

Regular Contributor
Posts: 163

Re: Single group comparison of incidence pre and post

Sample data:

 

ID       Time      Count     Total

1          pre         3           1200

1          post        5           1300

2          pre         0           1250

2          post        3           1310

..

 

 

I want to do by both county and overall. The event is very rare, I wondered if an exact poisson would be appropriate but we cannot use the repeated statement with an exact poisson. Any advice would be helpful.

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