How is Skill calculated?

On my BattleLog page I have a Skill rating.

What elements of the game effect this rating? Is it related to points gained per match, or wins? Kills perhaps?

I've noticed that my skill rating seems to fluctuate quite a bit between play sessions. Going from anywhere around 180 up to 250.

What are the maximums and minimums of this rating?

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Min = 0 Max = 1000 I think. I will have to verify this. – Zero Stack Nov 8 '13 at 21:52
You can see the global distribution of skill scores at this Battlelog URL. You have to be logged in. Click the little circled i next to your Division and a graph will pop up. At the moment 3% of the world has a skill of 303 or greater. A skill of 186 puts you in Division 6, or at about the median of all world players. – Nelson Nov 10 '13 at 16:00

Skill is normalized (as in between 0 and 1), but for display purposes it's multiplied by 1000 and rounded to nearest integer. In other words 100% perfect skill would be 1000. OTOH, someone scoring no points at all, would have score of 0.

As for how it's calculated, shortly after the question was posted here, it has been extracted from the game and posted on Symthic forums and subsequently on BF4 Reddit.

For a single game skill 60% of skill comes from SPM (capped at 1000), 30% comes from KPM (capped at 3.0), and 10% comes from KDR (capped at 5.0).

BTW. note that these calculations use SPM which excludes any bonuses and boosts (ie. as shown on scoreboard), while BattleLog displays SPM including bonuses and boosts.

To calculate this you first have to normalize each component:

``````normalized_SPM = min(SPM/1000.0, 1)
normalized_KPM = min(KPM/3.0, 1)
normalized_KDR = min(KDR/5.0, 1)
``````

Now apply the percentages :

``````normalized_skill = .6 * normalized_SPM
+ .3 * normalized_KPM
+ .1 * normalized_KDR
skill = round(normalized_skill * 1000)
``````

So above is skill for just one game. But what's is displayed in BattleLog is overall skill, which is calculated to the formula is 90% skill prior to current game + 10% current skill:

``````new_skill = round(.9 * old_skill + .1 current_game_skill)
``````

In the battle report you can also see how the skill changed, which is calculated as follows:

``````skill_diff = new_skill - old_skill
``````

Examples:

You had very intense game which lasted 20 minutes, in which you scored 5000 game points (not including bonuses and boosts), killed 30 people and died 45 times.

``````normalized_SPM = (5000/20.0)/1000 = .25
normalized_KPM = (30/20.0)/3 = .5
normalized_KDR = (30.0/45.0)/5 = .13
normalized_skill = .6*.25 + .3*.5 + .1 * .13 = 0.3133
this_round_skill = round(0.3133 * 1000) = 313
``````

So if you'd play all rounds like that your skill would be 313.

Now another example, suppose in the same 20 minute game you were camping instead, you got 1000 points, 6 kills, 0 deaths (which counts as 1 actually). As said KDR is capped at 5, so that's what you put into the calculation.

``````normalized_SPM = (1000/20.0)/1000 = .05
normalized_KPM = (6/20.0)/3 = .1
normalized_KDR = (5.0/1)/5 = 1
normalized_skill = .6*.05 + .3*.1 + .1 * 1 = 0.16
this_round_skill = round(0.16 * 1000) = 160
``````

OK, so suppose that you're starting skill was 186, in the first example

``````new_skill = round(.9 * 186 + .1 * 313) = 199
diff = +13
``````

In second example:

``````new_skill = round(.9 * 186 + .1 * 160) = 183
diff = -3
``````

So that's how it's calculated. This does not have anything to do with playing the objective, in fact if you just spam on Operation Metro, your skill is going to be way higher, than lets say trying to arm MComs on Operation Whiteout rush.

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The "Skill" stat actually has a brand new algorithm behind it that's very different from BF3 and is much more focused on PTFO

PTFO = Playing the f%\$&#^@ Objective

Therefore, the skill will fluctuate heavliy based on your participation towards the objective (attacking/defending, arming/disarming, squad work, etc), rather than just K/D.

Also, if you view the World leaderboards for Skill, it looks like 1000 is the max and 0 is the min.

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So "PTFO" does this mean the general map objectives or your squad/commander orders? I guess both count in some form? – David Yell Nov 9 '13 at 11:23
This answer is no longer valid given what learned later. gaming.stackexchange.com/a/215511/7354 – vartec Apr 27 '15 at 3:44

You gain or lose your skill, based on your kill/death rating. You gain skill for killing hight level enemy and losing less if they kills you. You lose skill when dying from low level players and get almost nothing for killing 'noobs'.

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Do you have a source on this? Sounds like speculation. I find it hard to believe that skill is based solely on kills/deaths, as that does not promote teamwork/objective based play. – turbo Nov 8 '13 at 16:57
It was the same in BF3. Think of it as ELO rating from chess. – Sentry Nov 8 '13 at 18:50
this is only partially true. KDR is taken into account, but win percentage, average score per game(much more weighted in the calculation, to ensure objective play), and your progression is also taken into account when calculating your rating. – Rapitor Nov 8 '13 at 21:19
I highly doubt K/D ratio has anything to do with skill.. In a game where I had 4,5 K/D(18 kills, 4 deaths) I got -2 skill. In a game where I had 2,2 K/D ratio(11 kills, 5 deaths) I got +24. Right now I'm at 333 skill and I have absolutely no idea what makes it go up or down. – user63222 Dec 6 '13 at 7:56

protected by Community♦Dec 6 '13 at 14:50

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