When the state mandates textbooks, it consistently produces second-rate textbooks that replicate the same flaws and failings over and over again. Adoption states perform poorly on national tests, and the market incentives caused by the adoption process are so skewed that lively writing and top-flight scholarship are discouraged.
View the PDF here.
If the issue of state mandated textbooks still interests you, read Maximillian Longley’s article, “Errors Persist in NC School Textbooks.”