Dear colleagues
When testing a Poisson model and we obtain a beta coefficient of -0.23, is this method of interpretation correct? I am curious to hear your thoughts about this method or whether you have a different interpretation.
-Take exponent exp
(-0.23) = 0.79 (this is for Y2/Y1)
-Take reciprocal to aid interpretation: 1/0.79 = 1.27 (this is for Y1/Y2)
-A unit increase in Y1 is associated with 27% increase in the outcome
Note: several people interpret this by subtracting 1 from the 0.79, but since this exponentiated value is under 1 I don't believe that is correct since I don't know what the lower limit is.
thanks!
Salma
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Salma Musaad
USDA/ARS Children's Nutrition Research Center
Baylor College of Medicine
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