Hi all.

I think that p-value is one of the most greatest way of measuring degree of observed data.

However, BLAST doesn't use p-value but E-value.

Why the BLAST use e-value for interpreting sequence data instead of p-value?

Is there any logical reason to use E-value for BLAST? If so, could you tell me the detail reason?
<p>Quote from the BLAST help (http://www.ncbi.nlm.nih.gov/BLAST/tutorial/Altschul-1.html#head4 ):</p>

<p><em>&quot;The BLAST programs report E-value rather than P-values because it is easier to understand the difference between, for example, E-value of 5 and 10 than P-values of 0.993 and 0.99995. However, when E &lt; 0.01, P-values and E-value are nearly identical.&quot;</em></p>

<p>Important to note that<em> </em>P value of the BLAST is not the same thing than a P-value of a t-test.</p>
