Re: st: Log of nonpositive numbers

[Daniel Schneider <daniel.schneider@stanford.edu>]

Income should not be negative. Wealth is not income. The studies that 
use something like this mostly use INCOME not WEALTH.

The question here is why you are using both wealth and income. In many 
(but not all cases) income is included as a general control variable 
reflecting social status etc. In that case you would probably be fine by 
just using income and perhaps using log(income+1) for those few cases 
that have zero income. I bet income and wealth are highly correlated 
anyways.



ucb_gal wrote:

> Hi,
>
> I've seen this question asked a few other times, but I'm still a little unclear on what the considerations are in thinking this through.
>
> I'm running logistic regressions with the log of income and wealth as independent variables.  I've seen this done often enough that I didn't really think twice about it.  But then I realized that while I don't have a ton of cases with exact 0 values in either variable, I do have a number of cases with negative wealth.  And all of these show up as missing now.
>
> Am I mistaken in thinking that I've seen studies that use the log of income as predictors??
>
> Thanks!
>
>
>
>
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