Normal scores are near 100%, if the stimulus is presented at 30 dB SL or above, at MCL or above. The hearing impaired probably will not have a normal score, but will miss some items.
When interpreting the word recognition score, it is important to consider the presentation intensity. A normal hearer would score poorly if tested at 5 dB SL. A score of 80% would not mean the person hears 80% of words correctly in everyday life if the testing had been conducted at the patient’s MCL of 80 dB HL (which is much louder than conversational speech). So, the intensity of presentation must always accompany the report of the percent correct.
It is simply not true that a score of X% means that a person hears that percentage of speech. Even if the testing was conducted at a conversational loudness, speech understanding is different from understanding single words presented in quiet in a test room. Speech has linguistic redundancy – the listener does not need to hear each word in order to understand the message. Word recognition testing uses single words, not contextual speech. Also, note that testing is conducted in a quiet test booth. The everyday world is usually rather noisy. Speech is usually only 8 dB louder than the background noise!