BookmarkSubscribeRSS Feed
🔒 This topic is solved and locked. Need further help from the community? Please sign in and ask a new question.
sasnewbie12
Obsidian | Level 7

Hi

 

I am conducting a study comparing two treatments. What difference will it make if I use age in the multivariate analysis to control for any confounding effects age (<=18 or >18) will have versus doing two different studies (one in adult patients only and one in pediatrics patients only). 

 

Thank you

 

1 ACCEPTED SOLUTION

Accepted Solutions
Reeza
Super User

Entirely separate analysis means that the variance is calculated differently whereas they're included in the model. Instead of separating it out entirely, you can also consider a STRATA variable. 

 

So your options are :

 

1. Separate models (BY statement)

2. STRATA statement - variance for both are considered

3. Model entry - variance considered, interaction terms possible. 

 

 

View solution in original post

2 REPLIES 2
Reeza
Super User

Entirely separate analysis means that the variance is calculated differently whereas they're included in the model. Instead of separating it out entirely, you can also consider a STRATA variable. 

 

So your options are :

 

1. Separate models (BY statement)

2. STRATA statement - variance for both are considered

3. Model entry - variance considered, interaction terms possible. 

 

 

PaigeMiller
Diamond | Level 26

As I see it, age should be treated as a continuous variable, because it is a continuous variable. If you do two different studies, you are now analyzing the data as if age was a discrete variable. Furthermore, someone who is 17 years 11 months is treated by the analysis very differently than someone who is 18 years one month. So, with all that in mind, I think the model would have greater predictive power if you treat age as a continuous variable. And not only that, the sample size used in the modeling is greater if you treat age as a continuous variable in one large analysis.

--
Paige Miller

sas-innovate-2024.png

Available on demand!

Missed SAS Innovate Las Vegas? Watch all the action for free! View the keynotes, general sessions and 22 breakouts on demand.

 

Register now!

What is ANOVA?

ANOVA, or Analysis Of Variance, is used to compare the averages or means of two or more populations to better understand how they differ. Watch this tutorial for more.

Find more tutorials on the SAS Users YouTube channel.

Discussion stats
  • 2 replies
  • 1233 views
  • 3 likes
  • 3 in conversation