If the tutor is working out of their own home, do they have an office area or learning area for the child. Most kids learn best in a minimal distraction environment that is structured and organized. Ask to see the learning or study areas and see if it appears orderly and structured.
Tutors that come to your residence to work with the child will need a place to interact with the child that is calm, quiet and free from traffic, televisions and telephones. Finding a place to hold a tutoring session may be difficult in a busy home and going to the tutors may be a logical option.