I don’t know SRI International, but i found these testresults on their homepage:
http://mtc.sri.com/live_data/av_rankings/
Most Effective Antivirus Tools Against New Malware Binaries
Mon Sep 1 08:34:57 2008
Their description:
DISCLAIMER: These detection rates represent the TRUE POSITIVE detection rates of these various antivirus tools on the limited corpus of malware binaries captures by our honeynet. The results do not take into consideration the false positive rate of a given tool, and thus a tool that declares everything to be infected would appear to have the highest true positive percentage rate. All antivirus results provided via www.virustotal.com.
Rank Detects Missed Product
1st 97% 94 AntiVir
2nd 96% 105 Webwasher
3rd 94% 171 Ikarus
4th 93% 207 BitDefender
5th 92% 255 AVG
6th 91% 269 F-Secure
7th 89% 357 Avast
…
EDIT: There is also a list of the missings from Avast:
http://cgi.mtc.sri.com/popups/av_rankings/08-31-2008/Avast_Missed_MD5s.html