[R] back transforming output from negative binomial

[Adaikalavan Ramasamy]

Ben, fantastic. Thank you for confirming it.

One more question. What do you call the back transformed variable?

In my domain, people use something called the ratio of mean but I am not 
sure if it is the same. I am not what the "ratio" is between.

Regards, Adai



Ben Bolker wrote:
> Adaikalavan Ramasamy <a.ramasamy <at> imperial.ac.uk> writes:
> 
>> Dear all,
>>
>> I used the glm.nb with the default values from the MASS package to run a 
>> negative binomial regression. Here is a simple example:
> [snip -- thanks for the example!]
>> The question now is how do I report the results, say, for height? Do I 
>> simply take the anti logs. i.e. 1.019613 = exp(0.019423) ?
>>
>> I have seen one paper where they report using anti log base 10 instead 
>> of natural base but they use STATA though.
>>
> 
>   Yes, exactly. If you look at ?glm.nb you
> will see that it uses a log link function, and therefore
> you should exponentiate (anti-log) to back-transform.
> Natural, not base-10 logs, are used.
> Don't forget that back-transforming standard errors
> by themselves is meaningless, you have to back-transform
> lower and upper confidence limits ...
> 
>   Ben Bolker
> 
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