It sounds like nearly 25% of people have a reference point to start with to prove that their new normal is sufficiently worse than what they started with: "Nea

It sounds like nearly 25% of people have a reference point to start with to prove that their new normal is sufficiently worse than what they started with: "Nearly a quarter of the plaintiffs ... reported their condition in hearing tests before they ever used the Combat Arms earplugs." That would seem to mean they have a "before" measurement, and can now test to get an "after" measurement.