A school abroad may have one American student, and no native speakers, yet they will portray they are teaching English classes, take extreme care here.
International Schools and American School abroad are willing to lie or misrepresent reality, when researching this topic never trust anyone, go to the school and visit.
Government web sites are well intended, and if you can find a person with children working in the USA government, I am sure they can help. But never, ever under any circumstance make a decision on this from written materials offered on Internet pages or brochures. Please, I beg you to go visit the school and interview the teachers.
As a rule of thumb, the place that are nicest to live, that naturally have the most foreigners living abroad have the best opportunities to recruit teachers. For example, the quality of living in Bangkok, a large city is not the same as Chiang Mai, therefore the reasons for living inside each specific city are different. One teacher may want to be there, while another is required to be there, the happiness of the teacher, what motivates the teacher should be considered for your children.
Warning: There are hundreds of great schools not listed on web site, why? Because they do not need to promote on the Internet, they thrive without huge marketing programs!
1. How many native speaker, name, and you need to meet them. They will portray a person with an American passport as being native, many people that were not raised in the USA, and truly do not speak English properly are pretentiously over-representing their English language skills, trust nothing but your eyes.
2. Why are the native speaking teacher there? What is motivating the teacher, generally the best teachers are probably ones who also have children attending the school. Many times the husband or wife is working for the USA or British Government, and the spouse teaches classes.
3. Do they have a degree, make sure they are truly qualified.
4. School Fees, and fine print, and cost involved, it will amaze you.
5. How books are purchased, where they are printed, preview the textbooks, make sure they are really in English.
6. Number of American citizen students or British, etc.
Tutors? I believe home schooling is often the best option.