Dear Members: Happy New Year 2011. I am wondering about what’s the 
difference between natural log (ln) and log to the base 10 (log) while 
calculating the Shannon diversity index. 

H = - summation [i=1 to s] (pi log pi)          for  i = 1...n.

Where, i = proportion of the population of group i (i.e. relative 
abundance), and s = the total number of groups.

What if I use natural log (ln) in the above formula? Is one method better 
than the other?

In my understanding log is generally taken to shrink the large numbers. 
Because in the above formula the proportion can range from 0 to 1 (which is 
already a small number, and standardized too), I am wondering about the 
logic of multiplying the “proportion” by its “logarithmic proportion”.

I would greatly appreciate your thoughts.

Sincerely,
Nabin

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