I will answer briefly as it is a very broad topic.
The quality of child care services is a construct. The research refers to structural quality, which includes ratios, compensation and staff qualifications. It also refers to the quality of the process, that is, the quality of interactions between staff and children, and between staff and parents. There are many aspects.
In North America, there are two measures that are used a lot: the ECERS scales, for the preschool level, and the CLASS system, the classroom assessment scoring system. The ECERS scales cover a whole range of factors, such as furnishings, personal care, activities, interaction, daily schedules, and so forth. The CLASS system is used to evaluate interactions during two 25-minute periods, but does not evaluate the overall environment. That is very important, however, so there is room for improvement in that regard.
Do I have any time left?