There is presently in wide use throughout the United States an assumption that alcohol treatment programs should be geared toward handling 20% of the alcohol problem prevalence population. This 20% figure has become so widely accepted that it is now almost axiomatic. The most frequently offered reason for its use is that“many other states use it.”The present discussion raises questions about the foundations upon which the 20% assumption is based. It then describes recent efforts to seek solutions to these and related questions.