* Non-excludability: It's impossible (or extremely difficult) to prevent people from consuming the good, even if they don't pay for it.
* Non-rivalry: One person's consumption of the good doesn't diminish another person's ability to consume it.
Elementary schools don't perfectly fit this definition:
* Non-excludability: While public schools generally aim for inclusivity, they *can* exclude students (e.g., due to disciplinary reasons, residency requirements, or lack of space). Private schools are explicitly excludable based on ability to pay.
* Non-rivalry: To a certain extent, adding another student to a classroom *does* diminish the resources (teacher attention, classroom space) available to existing students. This rivalry is more pronounced in overcrowded schools.
Therefore, a public elementary school is not a *pure* public good. However, it exhibits characteristics of a public good, particularly in its provision of education, which benefits society as a whole through increased productivity, civic engagement, and reduced crime. This makes it a *near public good* or what economists might call a *club good* (non-rivalrous up to a certain capacity, but excludable). The degree to which it's a public good varies depending on factors like funding, capacity, and school policies.