Here is what the law says:
“ONLY students in a public school, a public charter school as defined in section 2401, subsection 9 or a private school approved for tuition that enrolls at least 60% publicly funded students, as determined by the previous school year's October and April average enrollment, are required to participate in the system of learning results set forth in this section and in department rules implementing this section and other curricular requirements.”
A homeschool program does not have to comply with the Maine Learning Results (where Common Core has been placed), and Maine homeschoolers are not required to take the Maine Educational Assessment tests (MEA). Upon graduating, homeschool students receive a parent-generated high school diploma. If homeschoolers were required to meet the standards of the Maine Learning Results, these standards would drive each homeschool family's curriculum. This means that homeschool parents would be compelled to teach the same subjects, with the same content, at the same time they are taught in public schools. Teaching would be focused on the objectives of the Maine Learning Results, instead of individualized instruction, which is the foundation of successful homeschooling.
Although reviewing the Maine Learning Results may be useful to homeschooling parents who are interested in knowing the curriculum content of government school subjects, homeschoolers are not required to use them. More about the Maine Learning Results can be found at the Maine Department of Education website.
In addition, read Equivalent Instruction and Common Core in Maine.
NOTE: If a student transfers from homeschooling to a public school, he or she may be required to take one or more tests for placement or high school credit transfer. Transfer policies differ in each school district. Be sure to inquire. Keeping a good portfolio can help to make the transition to a public or private school smoother.
From the compulsory attendance law:
“(d) If the home instruction program is discontinued, students of compulsory school age must be enrolled in a public school or an equivalent instruction alternative as provided for in this paragraph. The receiving school shall determine the placement of the student. At the secondary level, the principal of the receiving school shall determine the value of the prior educational experience toward meeting the standards of the system of learning results as established in section 6209. [2007, c. 111, §1 (AMD).]”
Refer to the complete statute here.