So if testing on hundreds of additional songs beyond KRTH's 600 or so that they already play, that would make the testing total about 1000-1200 songs each session? And say 100 people are at a testing session, how many of those must pass a song for it to air on KRTH?
The number of people in a test is not relevant. It's more about the percentages and totally about the distribution of scores.
In other words, what is the range of most of the scores? It's not that there are songs that 30% of people love and 70% hate. It's more like there are songs that a few people like, some are neutral, and quite a few are at least moderately negative. So the score range for most respondents might be from 65 down to 40. In other words, a song with little interest, and considerable negatives.
In most cases, a station's research company will do things like cluster analysis, too. So a song has to perform well against the total group of respondents, as well as (to create examples) the younger part of the test, the older part, the men, the women, and maybe those who are members of important ethnic groups who like the format or station.
And you do realize that between 1968 and 1987, there are 2918 songs that charted in the top 20 positions, plus many album only tracks that have aired. Using these numbers, around 20% of those charted singles are being aired today (if KRTH has a 600 song playlist).
And, don't you think that all those other 2300 songs have been tested over the many years of KRtH's existence? Obviously, many songs were eliminated years and years ago. But the ones that might fit, as well as newer songs, are tested many times before being discarded as "impossible" tunes.
8 of every 10 hits from the 1968-1987 period are NOT being aired today. That's actually very discouraging.
It is what it is. That's the extent of consensus hits today.
I would be content with at least 50%.
I only wish we could buy you a radio station so you could prove to yourself that playing deep libraries will bankrupt you almost immediately in any rated market.