Training, when there is training at all, is on the spot. The turnover of daycare employees is a national scandal. Pay is minimum wage or close to minimum, the work is overwhelming and thankless and there is no chance for promotion. There isn't a job ladder to climb. But that's not, by any means, a fair description of all commercial daycare centers.
Good centers keep good providers year after year.
The questions most parents need to ask is, what's the turnover and the education requirements for the daycare, be they home-based or located at a commercial center. And it's never too much to ask for references. Family care, on the other hand, is usually owned and operated by a family in a private home. Ask a neighbor. Choose a family home that has a good childcare philosophy, incentive, purpose, energy and space, and the child-care can be excellent.