turn on suggestions

Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

Find a Community

- Home
- /
- Analytics
- /
- Stat Procs
- /
- Logistic Regression Type III analysis DF = 0 estim...

Topic Options

- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Email to a Friend
- Report Inappropriate Content

01-31-2012 05:01 PM

Hi, I ran a proc logistic on a binary response with a few covariates, some continuous and some categorical. When I checked the TYPE III analysis of effect, there is one line for a categorical covariate with DF = 0 and missing estimate. What is wrong here?

TYPE III Analysis of Effect

Effect DF Chi-square Pr>Chisqr

Age 1 58999.5037 <.0001

Indicator 0 . .

gender 1 3266.6988 <.0001

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Email to a Friend
- Report Inappropriate Content

01-31-2012 05:27 PM

What does proc freq on the variable (indicator) do, with similar modelling restrictions (ie any where clause you used)?

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Highlight
- Email to a Friend
- Report Inappropriate Content

02-01-2012 10:20 AM

Logistic Regression has a linear model component. If any variable can be expressed as a linear combination of others, then it will show up with 0 degress of freedom and no estimate.

For instance, if you had 0-1 binary variables called Female and Male, then <Female = 1 - Male> and one of them is redundant. Usually, it is not as bovious as my example and you might need to do some two way frequencies or correlations to tease out the dependency.

Doc Muhlbaier

Duke