Homeschooling and Private Schools Save Public School Money

In so many different ways. This study in Nevada says what I couldn't understand was ever a question.

The Heartland Institute notes Nevada's homeschooling regs:

The study also included information on Nevada's homeschooling regulations. To comply with the compulsory education law, students must attend a public school from ages 7 to 17, or receive equivalent instruction at a private school or home. They must receive instruction in English reading, comprehension, and writing; mathematics; and science.

When beginning to homeschool, parents must provide their district with information about the goals and materials they use and their eligibility to teach according to state criteria for homeschools. After this initial notification, parents must then inform the district annually of their intent to continue homeschooling.

Homeschoolers and privately educated students may participate in public school classes or extracurricular activities at the state's expense when space is available.
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Looks a lot like Illinois' except we require no notification; annually or initially:

Sec. 26‑1. Compulsory school age‑Exemptions. Whoever has custody or control of any child between the ages of 7 and 17 years (unless the child has already graduated from high school) shall cause such child to attend some public school in the district wherein the child resides the entire time it is in session during the regular school term, except as provided in Section 10‑19.1, and during a required summer school program established under Section 10‑22.33B; provided, that the following children shall not be required to attend the public schools:
1. Any child attending a private or a parochial school where children are taught the branches of education taught to children of corresponding age and grade in the public schools, and where the instruction of the child in the branches of education is in the English language;