Simple logistic regression is used for univariate analyses when there is one dependent variable and one independent variable, while multiple logistic regression model contains one dependent variable and multiple independent variables. To run univariate and mulitple Logistic Regression in SAS-callable SUDAAN, SAS, and Stata, you will need to provide three things:

- Correct weight
- Appropriate procedure, and
*model*statement

IMPORTANT NOTE

Simple logistic regression is used for univariate analyses when there is one dependent variable and one independent variable, while multiple logistic regression model contains one dependent variable and multiple independent variables.

It is always important to check all the variables in the model, and **use
the weight of the smallest common denominator**. In the example of univariate analysis, the 4-year MEC
weight is used, because the hypertension variable is from the MEC
examination. In the multivariate analysis example, the 4-year MEC
morning subsample weight is used, because the fasting
triglycerides variable is from the morning fasting subsample
from the lab component, which is the smallest common denominator for all
variables in the model.

Simple logistic regressions for gender, age, cholesterol, and BMI:

Because these analyses use 4 years of data and includes variables that come from the household interview and the MEC (e.g. blood pressure, BMI, HDL cholesterol), the MEC 4-year weight -

wtmec4yris the right one.

Simple logistic regression for fasting triglyceride:

Because this analysis uses 4 years of data and fasting triglycerides were only done on the morning subsample, the MEC morning fasting subsample 4-year weight -

wtsaf4yris the right one.

Multiple logistic regression:

Because this analysis uses 4 years of data and includes variables from the household interview, MEC and morning subsample of the MEC, the weight for the smallest group - the morning fasting subsample 4 -year weight -

wtsaf4yris the right one.

- See the Weighting module for more information on weighting and combining weights.

You can run logistic regression with stand-alone SUDAAN, SAS-callable SUDAAN, SAS Survey procedure, or Stata Survey commands. However, note that each version of SUDAAN, SAS-callable SUDAAN, and SAS Survey procedures has its own unique commands for executing logistic regression analysis. You need to use the correct command for the software that you are using. Please also note that different versions of SAS and SUDAAN use slightly different statements to specify categorical variables and reference groups. Make sure that you are using the correct commands for the version of software on your computer.

If you use

- the
**stand-alone version of SUDAAN**, the procedure is*logistic* **SAS-callable SUDAAN**, the procedure is called*rlogist***SAS survey procedures**, the procedure is*surveylogistic*

Be sure you are using the correct procedure
name because **SAS** also has a procedure ** logistic**, which is
used with

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Remember that when you run logistic regression analyses, you
must provide a *model* statement to **specify the dependent variable
and independent variable(s)**, and you can have only one *model*
statement each time you run a logistic regression analysis.