Have a look in the scientific literature. A lot of numbers, either successes and failures are well reported. Although some statistical analysis can be biased somehow and not every data set is really and completely significant, the overall advantage of CI over HA emerges pretty clearly.
Deafdude, you are right saying that the most of people who shift to CI do not get the maximum from HAs. I believe this is extremely difficult and time consuming. One should try different HAs (think about the costs here), several different settings, get used to every single change and only after a long time (many years?) being able to derive a result.
My thoughts go to the children: this is so difficult for adults, how the hell can it be possible with babies? You can find that HAs, even at their best, cannot help and you are over the deadline for having the most from CI. It is a matter of fact that young children implanted around 2 years of age usually performs very good. I met some of them, completely or profoundly deaf able to score nearly 100% and anyway able to discuss with me in a real life environment, without any apparent problem (and they are very young, 4.5 to 6.5). Could they reach this results in such a short time with HAs? Better, besides the completely deaf, could they reach similar results at all?
Statistics and these cases I experienced personally seem to tell that CI are much easier to be programmed than HAs over a certain amount of hearing loss.
You deafdude are a clear example of a person with an important HL, very well aided, extremely competent in understanding how a HA can help, performing significantly good, but you can understand 50% of what your dad says without lipreading. What about unknown people in a general environment?
I agree on the correlation about db and speech comprehension, there is for sure a link. Anyway the function is not linear, definitely. The correlation between audiogram and speech comprehension is extremely complex. Getting the most out of a HA is very important and can give good results. Still expectations cannot be even close to that a CI can give. For profound deaf people HAs can be a big help, but it is difficult they can enable listening to the radio or TV (without subtitles), or hearing in difficult environments... CI cannot guarantee it, maybe only a few reach that level, but there are at least those few... It's a matter of expectations, or better of hopes and opportunities.
Since it is obvious that audiogram cannot be the explanation (CI hardly can do better than 30db across the board, you are teaching to me), there should be something else. I would like to understand what's that.
