Not until Umbridge turned up.

We learn from Umbridge that there was a Ministry-sanctioned syllabus for Defence Against the Dark Arts. It was, however, ignored by most of the DADA teachers.

"The constant changing of teachers, many of whom do not seem to have followed any Ministry-approved curriculum, has unfortunately resulted in you being far below the standard we would expect to see in your O.W.L. year."
_{(Order of the Phoenix, Chapter 12, Professor Umbridge).}

Umbridge, of course, followed this curriculum to the letter.

"We will be following a carefully structured, theory-based, Ministry-approved course of defensive magic."
_{(Order of the Phoenix, Chapter 12, Professor Umbridge).}

Most teachers wouldn't have cared much what the syllabus put forwards by the Ministry was. Dumbledore effectively gave his teachers free rein, meaning that the terrible teachers like Lockhart were allowed to teach terribly (and set their own titles as school textbooks to push themselves up the bestseller list).

As the question suggests, what counts is how students perform in exams. Teachers would've been judged on the performance of their students. As long as the children are able to perform well and receive a decent all-round education neither Dumbledore nor the Ministry took a great interest in the contents of the lessons themselves. Umbridge's era was a break from the norm in this regard.