As others have said, taking a lesson with a teacher is the best way to see if your child connects with the teacher. My S got a lot of recommendations of teachers to look into from his own teacher at the time and also from some friends a year older who were also looking to study cello. We’re lucky to have a strong regional youth orchestra in our area so talking to other students and parents about where they were looking helped. We also found that when we were visiting a school for a lesson if we could also sit in on a studio class that gave us some additional information on the relationship that a Professor had with his students and the level of playing in his studio.