Statistics for 2007 show that in most technology fields, the BPAI affirms the examiners about 50% of the time. Notable exceptions are in TC 1700 (Chemicals and Materials) and TC 2900 (Designs), where 2007 affirmance rates were 68% and 75%, respectively. Note that these numbers do not consider cases where the BPAI does not rule on an appeal, such as situations where an Examiner reopens prosecution after reading an appeal brief. Presumably, appellants’ success rates would be a good bit higher if those situations were considered.

http://ipspotlight.com/2008/01/21/us...

Be well