I think Adrian is right although 3 is probably the average rather than 2. Even so, how many courses are really below average to the point where one would say it sucks (essentially 0, 1 and maybe 2)? I don't think we can look at golf courses in terms shit, poor, average, good and excellent. The worst course I have seen in England is unfortunately the closest to my house - Bidford Grange. Even with all its faults there is enough there to give it a 2 or 3 on the Doak Scale, but it doesn't matter for me because I won't go back unless its free and for a good reason. To me, the Doak Scale loses credibility at the high and low end as this is where opinion (or pet peeves/favourite concepts) really take over. I have seen a lot of rough n' ready munis and I still don't think I have seen anything less than 2-3.
Ciao