I read this question as an insult. How could they not know they are better at their job after 17 years of doing it?
This is just my personal opinion but the true judge of a teacher's effectiveness is how much their students learned, and even that can only be used as a measure if the students were willing to learn in the first place.
Relying on some national standard to judge teachers hasn't seemed to help any country in history to have better teachers. I'd wager to guess that periods in history where education unilaterally improved are more due to the motivation of those being educated than anything else.