[R-sig-eco] Log transforming zero value data

[Nate Upham]

I have a general stats question for you guys:

How does one normally deal with zero (0) values when log transforming data?  

I would like to log transform (natural log, ln) several response variables for use in quantile
regression.  But one of my variables includes several zero values.  Since ln(0) = infinity, this is
not readily possible.  Is it best to remove all data with zero values?  Or should I add a very small
number to each value (e.g., 0.00001)?  This seems problematic.  Is there an easy way to address this
issue?

Thanks much for your help,
--Nate

_________________________________
Nathan S. Upham
Ph.D. student
Committee on Evolutionary Biology
University of Chicago
1025 E. 57th St., Culver 402
Chicago, IL 60637
nsupham at uchicago.edu