The problem with thinking you're good at a non-quantifiable, hard to measure thing is that almost everybody thinks they're better than average at them. Are you sure you aren't just measuring your previous methods of teaching against your current methods? There's no way they can hold up if you use that measure, but that doesn't mean your current methods are better.

When I was a student I didn't notice much difference in teaching ability unless the teacher hand only been teaching for a couple of years.