From: Laval Hunsucker <[log in to unmask]>
Date: Wed, 12 Sep 2012 14:55:23 -0700

> Does anyone know of a comparison study that has been
> performed?

Ken,

Hasn't this or a very similar question been posed here before ?
I seem to recall something like that, but I could easily be wrong.
One could check the list archive.

What quickly comes to mind, at any rate, is Howland et al.,
"How scholarly is Google Scholar? A comparison to library
databases", _College & research libraries_ 70.3 (2009), p.227-
234.

In addition, a good number of comparative studies have been
published pitting GS against specific individual databases or
against certain databases for a given field/discipline. And they
continue to be published. A new one even appeared this month,
for example ( by coincidence in the field which probably most
interests you personally ) :  Nourbakhsh et al., "Medical literature
searches: a comparison of Pub Med and Google Scholar", _Health
information & libraries journal_ 29.3 (2012), p.214-222.

Sorry for the very hasty response.

- Laval Hunsucker
Breukelen, Nederland