A co-op preschool typically has one paid employee, the teacher, and a handful of parent volunteers who run the activity stations. The parent helpers take turns working at the preschool (typically 1-2 days per month) as a requirement for their child's attendance. There is a parent board (elected by the other moms and dads) that makes decisions on school policy such as the cost of tuition, food choices for snack time, fundraising efforts, and upkeep of the facility. The teacher makes the day-to-day classroom decisions: curriculum, discipline, daily schedule, and field trips.
The advantages of a co-op preschool are numerous: the incredibly low adult to student ratio (something like 1 to 5), the commitment of like-minded parents who believe their involvement makes a huge impact in their children's education, the multitude of activities the kids get to experience each day, and the low cost compared to other programs. A co-op preschool is both democratic and transparent. It's an ideal place for moms and dads who want to meet other parents, set up play dates, and be involved in a tight-knit community. The primary disadvantage is that belonging to a co-op preschool is quite challenging for working parents unless they're self-employed or have extremely flexible bosses.
In my current position, I visit dozens of early childhood education facilities each year, and I'm most impressed by the co-op preschools.
The youngsters get a wide-range of experiences that are fun and developmentally appropriate because of the parent helpers. Children aren't cruelly subjected to practices that are designed for older kids such as writing in workbooks, sitting still for long circle times, and listening to boring lessons about the calendar and weather. They're constantly moving, playing, pretending, interacting, exploring, and communicating.
At the co-op preschool, I visited last week, there was one parent who supervised outside while kids pedaled their tricycles and splashed at the water table. There was a second parent who assisted with the children painting at the easels. A third parent worked at the “sensory table” as youngsters explored a tub of cold colored spaghetti. A fourth parent helped with kids in the play kitchen, and a fifth was in charge of a group that was building with little hammers, nails, and pieces of wood. The teacher walked throughout the school, talking to the kids, asking them questions, and making sure everything was running smoothly. Everyone child was fully engaged, happy, and productive. It was what I would hope for every preschooler.
I have an article called “Why Parent Should Choose a Preschool With a Strong Philosophy: Montessori, Waldorf, or Co-Op” (https://hubpages.com/education/Montessori-Waldorf-... that you may find helpful.