League of Legends announced that they are adding new stats to the game. Instead of relying on your KDA, who got the most kills, as well as who dealt the most damage in the game, you'll now have other stats to play around with and compare with your friends.
One of those stats is called "Vision Score".
According to Riot GMang, Vision Score is, "Vision Score is a loose measurement of vision game contribution, and can be ballparked as "about 1 point per minute of ward lifetime I'm responsible for providing/denying." It tends to be in the 5-150 range."
Vision Score will help show you when you deny vision as well as when you reveal things. The goal is to have a more "meaningful and trustworthy number for players to analyze and compare performance."
Vision Score System
According to Riot GMang, "The "scale" of the point system is "every point of Vision Score is about equal to one minute of ward lifetime in value." So if your vision score at the end of a game is 121, you can ballpark "my vision contribution this game was worth about 2 hours of ward lifetime." This number comes from three main sources:"
Those three sources are Ward Lifetime Provided, Ward Lifetime Denied and Vision Mechanics.
Ward Lifetime Provided: "Each minute of ward lifetime you provide by placing wards will give you 1 point (can give fractions of points). There are actually a lot of modifiers to this score, see "Ward Lifetime Provided Modifiers" below."
Ward Lifetime Denied: "When you get a ward takedown (earned gold from a ward's death), you get 1 point for every minute of lifetime remaining on the ward (permanent wards are assumed to have 1.5 minutes of lifetime remaining)."
Vision Mechanics: "Various vision-providing mechanics have a baseline score on-use (usually 0.1 to 0.5), and can also give bonus scores if revealing unseen champions or epic monsters (usually 0.1 to 1.0). This includes Scryer's Bloom, trinket activation, ward placement, Scuttler Ward, Ashe Hawkshot, Kalista Sentinel, and Quinn Heightened Senses. A Hawkshot that reveals a full Baron attempt will give much more than a Quinn W that reveals nothing (which will still give some score)."
Your vision score can be in single digits, all the way up to over 100. Your score will be higher based on how much of your game you attribute to vision.
Ward Lifetime Provided Modifiers
"The rule of "my wards give me 1 point per minute they're alive" actually has a bunch of rules that can reduce the score. Each of these reduces the score multiplicatively: if two rules each reduce the point value by 50%, the resulting ward will give 0.25 points per minute, not 0 points. Modifiers only apply to the value from their actual duration: getting a -50% modifier for 6 seconds will translate to -0.05 points, not a -0.5 reduction from the entire minute."
Wards can be effected by staleness, redundancy, safety, pointelessness, and baseline.
Staleness: If a ward doesn't see any units, it will decrease in point value
Redundancy: If a ward is completely useless because of another ward or vision point, it becomes redundant.
Safety: A ward that is close to your base will give you less score.
Pointlessness: If you ward on accident near something that already has a ton of vision, it's pointless.
Baseline: If a ward is quickly killed by enemies, it will still give a score as if it survived a minimum of 20 seconds (0.33) points