linked - Investigating the Terror

We have reached several conclusions regarding Williams' testimony.
First, Williams lacked the requisite scientific knowledge to testify
competently in this area. When Jourdan initially discussed the calculation
of potential urea nitrate, Williams appeared to Jourdan not to understand
the concept of a limiting reagent. His testimony makes clear that he
never learned the concept. Urea is not always the limiting reagent and
was apparently not the limiting reagent here. Moreover, in his
memorandum Jourdan explicitly defines limiting reagent as
stoichiometrically you run out of it first and finds nitric acid to be the
limiting reagent based on the information he was given. Accordingly,
Williams' testimony was inconsistent with the Jourdan memorandum.
Moreover, assuming that urea was the limiting reagent in this case,
Williams' numbers do not add up. Because, as earlier noted, 60 pounds
of fully reacted urea will produce 123 pounds of urea nitrate, 1200 pounds
of urea will produce a theoretical (100% yield) of 2460 pounds of urea
nitrate. A 90% yield would produce 2214 pounds (not 2100 pounds), and
a 60% to 70% yield would produce 1476 to 1722 pounds (not 1200 to 1800
pounds). The errors in Williams' calculations conveniently produced a
range that included the exact amount of urea nitrate--1200 pounds--that
he later testified was used in the Trade Center bombing.
Second, Williams' discussion of laboratory yield was problematic.
Williams testified that in a laboratory type environment the [b]est case
scenario would be a yield in the neighborhood of 90 percent. In his OIG
interview Williams said he got the 90% figure from Whitehurst or
Burmeister, although they do not confirm this. Assuming they said it, we
nevertheless question Williams' choice of words, which implied that his
testimony about laboratory yield was based on his own expertise. A
laboratory yield for a chemical reaction is obviously outside Williams'
area of expertise. He told us in his OIG interview that he had no way of
knowing, independent of the chemists, the accuracy of the 90% number,
but believed he could rely on the opinion of other experts in his
testimony. An expert may rely on opinions of other experts if this is the
normal practice in the field. See Fed. R. Evid. 703. Accordingly, Williams
would have been fully justified, in rendering his own opinions, in relying
on the chemist's statement about yield. For example, he could have
testified, My opinion is based in part on the statement of Chemist W, who
told me 90% is the best yield. But if he had so testified (with an
attribution for the yield statement), the court would have known on whose