The original schools were in Milwaukee—high poverty, high minority, high second language. Since then, the 90-90-90 techniques have been replicated all over the country with multiple language and ethnic groups. The school in California that had the highest achievement gains for two consecutive years, Mead Valley Elementary, was 100% poverty and 99% Latino and second language, and used 90-90-90 techniques. It's also been replicated in deep south rural schools, Native American schools, and many other schools with diverse ethnic and linguistic backgrounds.

What percentage of the population in the studies were ELL and special education learners?

We have worked with 100% ELL schools and with schools that have full inclusion. In some cases, more than half the students with IEPs, including students with autism, ED, LD, and developmental delays, met or exceeded state standards, with the only adaptation on the state test being time.

Are there effective resources/best practices in the area of writing to deal with a significantly large ELL population?

See the new books Reason to Write and the Reason to Write Student Handbook for more elaboration here. In general, the keys for ELL students include multiple opportunities for success, multiple ways of representing ideas (writing, oral, webs, pictures), and focused feedback. By "focused feedback" I mean don't try to do grammar, organization, word choice, simile, metaphor, irony, and spelling all at the same time. With my ELL students, I would start focusing on JUST organization - beginning, middle, and end. If we had that, it was worthy of celebration. Then I might add just ONE convention, such as capitalization or ending punctuation. Incremental steps, regular feedback, and opportunities for IMMEDIATE correction and success.