A recent national study of the public schools shows that there are now

This is something that I got from the Princeton Review Verbal Workout (downloaded from https://64168.com/bbs)

The misplaced modifier rule applies to phrases, but not to clauses.

Fo the benefit of others (and to save my own time), I'm copy-pasting the OCRs version of the relevant text from the Workbook here

Most misplaced modifiers come down to making sure that the opening phrase, followed by a comma, modifies the subject of the sentence. There is a possible solution to other problems, however, that don't occur very often on the GMAT. As the Grammar Glossary will tell you, there is a fundamental difference between a phrase and a clause: A clause contains a subject and a verb, and a phrase lacks either a subject or a verb.

Clause: Although he looked for his glasses for hours,
Phrase: Having looked for his glasses for houfs,

See the difference? If you take away Although from the clause, you have a complete sentence: He lookedfor his glassesfor hours. The phrase, however, has no chance to stand by itself as a complete sentence. The misplaced modifier rule applies to phrases, but not to clauses. Therefore:

You can change a misplaced modifier into a legal sentence by changing a phrase into a clause.

Here's an example:

Wrong: While leaving the bank, Evelyn's purse was stolen.
Right: As she was leaving the bank, Evelyn's purse was stolen.

The opening phrase is now a clause (with the subject she and the verb was), so it's okay.

HTH