Legislation may mandate staffing ratios (for example, 6 weeks to 12 months, 1:4; 12 months to 18 months, 1:5; 18 months to 24 months, 1:9; etc.). The caregiver-to-child ratio is one factor indicative of quality of care. Ratios vary greatly by location and by daycare center. Potential consequences of a caregiver:child ratio which is too high could be very serious. However, many states allow a higher numbers of toddlers to caregivers and some centers do not comply consistently. For example, within the US: Pennsylvania, ages 1–3, 1 teacher to 5 children; Missouri: age 2, 1 teacher to 8 children; North Carolina: 1 teacher to 10 children.
The first crèche was opened by Firmin Marbeau on 14 November 1844 in Paris, The Société des Crèches was recognized by the French government in 1869. Originating in Europe in the late 18th and early 19th century, day cares were established in the United States by private charities in the 1850s, such as the Charity Organization Society founded by Ansley Wilcox. The Fitch Creche in Buffalo, New York was known as the first day center for working mothers in the United States. Another at that time was the New York Day Nursery in 1854.