Is there a numeric value on vision so that I can see the increase or decrease of vision from year to year?

the best thing to do is keep track of the role rating you see for each position each recruiting season.

If last year the highest rated QB you could see was 39.6 and then next year the highest QB you could see was 41.4....then your vision went up. If you win 14 games each year, your vision will stay around the same. But, if you win 14 games two years in a row....then 11 games....then 13......you will see a drop in your vision. And, vice versa if you mix in a 15 or 16 win season.

That is prob as good a way as any to figure it. I used to just add up how many TE's I could see every season . If number went up I figured so did my vision.
But in lower levels for simplicity sake, you want to win as many as you can for a few seasons. General guess is 3 or more. And then you should see quality of your recruits and number of quality recruits go up.

What I do is, I wait until the season has changed over completely, before I add new players to my recruiting board. That way, if your vision goes down, you won't have players on your board that are outside of your vision.

What I do is, during the current season I put the #1 player in my vision at each position in my watch list. Then after rollover, I see how many players at each position are higher than those players in the watch list. The only thing to look out for, though, is making sure those players in your watch list are still in your vision. Sometimes they will drop out.