BookmarkSubscribeRSS Feed
saurabh1
Calcite | Level 5

Hello,

 

I am doing logistic regression in R on a binary dependent variable with only one independent variable. I found the odd ratio as 0.99 for an outcomes. This can be shown in following. Odds ratio is defined as, ratio_odds(H) = Probability(X=H) / (1-Probability(X=H)). As given earlier ratio_odds (H) = 0.99 which implies that the probability (X=H) = 0.497 which is close to 50% probability. This implies that the probability for having a H cases or non H cases 50% under the given condition of independent variable. This does not seem realistic from the data as only ~20% are found as H cases. Please give clarifications and proper explanations of this kind of cases in logistic regression.

 

Thanks all for your help!

2 REPLIES 2
Reeza
Super User

If you're using R, why are you posting to a SAS forum? Casting a wider net for an answer to your question?

 

IMO a question like this should be posted on stats.stackexchange.com

Ksharp
Super User
1)Maybe you missed some important independent variables .
2)Maybe the Scale for independent variable is too small . E.X. the dose of medication :  1ml v.s  100ml . 
   Check PROC LOGISTIC 's  UNIT statement.
3)Maybe there are some none-linear effect between  independent variable and dependent variables.
  Check PROC LOGISTIC 's  EFFECT statement.

4)Why not use Decision Tree or Random Forest in R ?

sas-innovate-2024.png

Join us for SAS Innovate April 16-19 at the Aria in Las Vegas. Bring the team and save big with our group pricing for a limited time only.

Pre-conference courses and tutorials are filling up fast and are always a sellout. Register today to reserve your seat.

 

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
  • 1271 views
  • 4 likes
  • 3 in conversation