Dear Dick, Chuping, and auditory.org list:
Thank you (Dick) for your summary of Brian Moore's talk. I wasn't present, but I am familiar with Brian's ideas on this topic.
Contrary to Brian's assertion that the audiogram isn't enough, I have had considerable success predicting speech intelligibility scores for hearing-impaired listeners using just the audiogram. I use Harvey Fletcher's full-blown Articulation Index [H. Fletcher and R.H. Galt (1950), J. Acous. Soc. Am. 22, 89-151]. To use the AI, I model the hearing loss as noise, and calculate expected masking spread for any external noise, and then plug these into an otherwise unaltered Fletcher calculation.