Calcite | Level 5

## proc genmod estimate statement

```proc genmod data = eyestudy;
class carrot id;
model lenses = carrot/ dist = poisson link = log;
repeated subject = id/ type = unstr;
estimate 'Beta' carrot 1 -1/ exp;
run;```

above was copied from below:

https://stats.idre.ucla.edu/sas/faq/how-can-i-estimate-relative-risk-in-sas-using-proc-genmod-for-co...

Above statement allows exp(beta) and exp(confidence intervals).

But I don't understand, the part of estimate statement, 1 -1.  Is it because carrot is binary variable?  If the variable has more than 2 categories or continuous, how estimate statement will be different.  I would very much appreciate your help!

2 REPLIES 2
Calcite | Level 5

## proc genmod estimate statement

```proc genmod data = eyestudy;
class carrot id;
model lenses = carrot/ dist = poisson link = log;
repeated subject = id/ type = unstr;
estimate 'Beta' carrot 1 -1/ exp;
run;```

above was copied from below:

https://stats.idre.ucla.edu/sas/faq/how-can-i-estimate-relative-risk-in-sas-using-proc-genmod-for-co...

Above statement allows exp(beta) and exp(confidence intervals).

But I don't understand, the part of estimate statement, 1 -1.  Is it because carrot is binary variable?  If the variable has more than 2 categories or continuous, how estimate statement will be different.  I would very much appreciate your help!

Sun

SAS Employee

## Re: proc genmod estimate statement

Yes, it is because it has two levels.  The number of coefficients will correspond with the number of levels and the ordering of the levels.

There are a number of good examples and explanations of estimate/contrast statements found here:

http://support.sas.com/kb/24/447.html

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