The metric for the hearing loss is easier to quantify, like with the audiogram. But even the ability to hear pure tones is very different than the ability to hear more complex, real life sounds. Pure tones rarely exist in real life.
Even the WRS is still a rather pretty crude metric to measure the degree of the hearing loss, because perception plays a big factor in it, and even between two people who hypothetically have the same hearing loss, one may have the ability to guess the words better than the other person. Many other factors are involved, their ages, brain acuity, mental sharpness, etc.
So if the metrics to measure the hearing loss is already pretty rudimentary to come up with, the metrics to measure the benefit are probably even harder to standardize.
On top of it, listening environments vary greatly. While it may be easy to standardize and simulate a simple listening environment at an audiologist office (if the pros are even so inclined to do), the much more important thing to measure is how well a patient does with a particular hearing aids in THEIR OWN REAL listening environments. How do you standardize and simulate that? It’s just way too broad and subjective and personal. There’s no guarantee that a person doing better in the WRS with hearing aid A compared to hearing aid B in a sound-proof audio booth will do better with hearing aid A in their own real live listening environment. They may be surprised to find that hearing aid B still actually outperforms hearing aid A in real life. The WRS test is so rudimentary that in no way it can or should affect the decision to select one hearing aid over another.
This is an inherent issue that’s already well implied by many patients’ acceptance that they simply need to go try out the hearing aid in their own real world to see if it works out for them or not, simply because there are just way too many personal variables involved.
I’m an engineer and I consider myself disciplined and logical in my trade and thinking as well, but I wouldn’t want to waste time asking my provider to rerun the WRS test for me after I’ve been fitted with a hearing aid. I won’t allow the WRS after-fitting result to be the judge of how well I think a hearing aid performs. The real judge to me is how well it does in my own personal and subjective listening environments. That’s the ultimate test that can’t be standardized and implemented in any professional’s office.