Why the Index exists
Nobody could answer the first question
How many Deaf children does your state educate? Where are they placed? What money follows them, and who runs the school that serves them? In most states no single public source can answer even one of those questions, and in some states no public source can answer any of them.
Federal reporting aggregates hearing-related categories in ways that dissolve the distinctions that matter, state education agencies publish to inconsistent standards or not at all, statutes have never been read side by side, and hundreds of district websites, some of which no longer belong to the districts, hold the rest. The Index reads all of it, every statute, every data file, every district site in frame, and writes down exactly what is there, exactly what is missing, and exactly where it came from.
Two formulations appear in the same words in every state file, because they are the boundary of what the Index claims.
NONE FOUND is a statement about publication, not about service delivery.
Obligations under IDEA are not evidence of a program.