Bungie.net Original Post URL: http://halo.bungie.net/Stats/Content.aspx?link=h2statoverview

Halo 2 Stats Overview

When you complete a matchmade game your stats are recorded for the matchmaking playlist that you played in only. These stats are then used to calculate your experience for that playlist. The end result is that each player has separate stats for each ranked matchmaking playlist. These stats are summarized in the form of a “level” for each playlist. If you’ve never played a game in that playlist you will have no level. New players start at level 1, the highest level is 50. Most players have levels closer to 10.

Levels are represented by level icons, shown below. The Friends, Clan, and Recent Players lists show a player’s highest individual level achieved. The Pregame Lobby, Matchmaking Screen, and Postgame Carnage Report all show a player’s level in the current matchmaking playlist. If the current playlist is a Clan playlist then the Clan’s level in that playlist is shown instead of each player’s level.

Level Icons

Click here for updated graphic including ranks 44-50.

Levels, as you have probably already realized, are important for more than just bragging rights. Your level corresponds to your skill at games in a particular matchmaking playlist. Games against similarly skilled opponents and with similarly skilled teammates tend to be the most fun. Thus skill (level) is one of our matchmaking systems most important criteria when searching for games. In fact, the matchmaking system prefers games with opponents of the same or very nearly the same level, and if it must stretch these boundaries it will not match players beyond the following limits.

Level	Maximum Match
1	+10 Levels
2	+9 Levels
3	+8 Levels
4	+7 Levels
5	+6 Levels
6	+5 Levels
7-16	+6 Levels
17-26	+7 Levels
27-29	+8 Levels
30	+9 Levels
31	+10 Levels
32	+11 Levels
33	+12 Levels
34	+13 Levels
35	+14 Levels
36+	Level 50

Note: This chart and all others in this article are controlled by Bungie and may change.

The only exception to this rule is when groups of players that exceed these limits enter matchmaking together as a party. When this happens the lower level player is treated as a player of minimum acceptable level for all matchmaking and experience calculations. For example, if a level 12 player forms a party with a level 1 friend, because the level 12 player can only match with levels 6 and higher, the player at level 1 will be considered level 6 when finding matches and calculating experience. This will put the less experienced player at a disadvantage, possibly in over his or her head, so be careful!

Level Calculations

Alright, on to the pressing question: How are levels calculated?

Halo 2’s stats system is actually pretty simple. When you win a game in a ranked matchmaking playlist you earn experience points. When you lose a game in a ranked matchmaking playlist you lose experience points. Your total experience points determine your level. Simple.

Well, alright, there are few things that complicate this system. If you only ever played the Head to Head playlist against one other player this would make sense. But Halo 2 supports games with up to 16 players. And team games. And games with up to 16 players and 8 teams! How does that work, huh!?

Alright, alright, don’t get antsy. It really is a simple system. Let me explain. For discussion purposes it’s useful to think of a free-for-all game as a game where every player is his own team.

First off, the only thing that matters for experience and level calculations is your current experience points and your team’s final standing, your place at the end of the game. It doesn’t matter how you got there, and it doesn’t matter whether you were the one that planted the flag or that got the most kills on your team. All that matters is the end result that your team achieved. Let’s say JoeBoy, Sly, SueMe, and Ralf all play a game with the following results:

• Sly: 1st Place
• JoeBoy: 2nd Place
• SueMe: 3rd Place
• Ralf: 4th Place

Halo 2 will calculate experience gained or lost first for Sly vs. JoeBoy, then for Sly vs. SueMe, then for Ralf, then total it all up and divide by 3. The result is Sly’s change in experience points, in this case positive. In SueMe’s case the game will calculate vs. the other three and divide by three. This means that SueMe gains points for beating Ralf but loses points for getting beat by Sly and JoeBoy. SueMe’s final experience point change will be negative, but not as bad as Ralf’s will be, as she earned something for beating him.

This same concept applies to teams. Experience change for a member of a team is calculated vs. every other member of every other team, then averaged.

Alright, on to Levels. Your level is nothing more than an abstraction of your experience. All new players start at level 1. There are 50 levels total. Which level your experience corresponds to is determined by the following chart.

Level	Min XP	Max XP	Level	Min XP	Max XP
1	1	99	26	4250	4499
2	100	199	27	4500	4749
3	200	299	28	4750	4999
4	300	399	29	5000	5249
5	400	499	30	5250	5499
6	500	599	31	5500	5749
7	600	699	32	5750	5999
8	700	799	33	6000	6249
9	800	899	34	6250	6499
10	900	999	35	6500	6749
11	1000	1099	36	6750	6999
12	1100	1199	37	7000	7249
13	1200	1399	38	7250	7499
14	1400	1599	39	7500	7749
15	1600	1799	40	7750	7999
16	1800	1999	41	8000	8249
17	2000	2249	42	8250	8499
18	2250	2499	43	8500	8749
19	2500	2749	44	8750	8999
20	2750	2999	45	9000	9249
21	3000	3249	46	9250	9499
22	3250	3499	47	9500	9749
23	3500	3749	48	9750	9999
24	3750	3999	49	10000	10249
25	4000	4249	50	10250	1 Billion

Experience Calculations

We know, this is all just a bunch of mumbo jumbo. And that stuff about the player being like the team is just confusing. And without knowing how many experience points are up for grabs in a game none of this really has any meaning. Hang in there.

You may have heard the term “ELO” bantered about in reference to Halo 2. ELO is a statistical system for calculating skills developed by Arpad Elo to track chess rankings. Our system is similar to ELO in that experience changes are based solely on the game’s final outcome. In addition, the resulting points gained or lost are not fixed. Instead point changes are determined by comparing the winner’s skill to the loser’s skill. You don’t really need to know much more about the system to understand how Halo 2 experience works. Basically, when we calculate experience point change at the end of a game we consult the following chart.

Experience Exchange by Level Difference

Level Diff	Higher Win	Higher Loss	Lower Win	Lower Loss
0	100	100	100	100
1	92	108	108	92
2	85	115	115	85
3	79	121	121	79
4	74	126	126	74
5	70	130	130	70
6	66	134	134	66
7	63	137	137	63
8	60	140	140	60
9	58	142	142	58
10	56	144	144	56
11	54	146	146	54
12	53	147	147	53
13	52	148	148	52
14	51	149	149	51
15+	50	150	150	50

Let’s go back to our previous example for a minute and assign these players levels:

• 1st Place: Sly (Level 10)
• 2nd Place: JoeBoy (Level 7)
• 3rd Place: SueMe (Level 8)
• 4th Place: Ralf (Level 5)

First we’ll calculate experience change for Sly. Sly (level 10) beat JoeBoy (level 7). They’re 3 levels apart, so we consult the 4th row down in the above chart to learn that Sly, the higher level player, gains 79 points. Sly also beat SueMe (8), but this time because SueMe is closer in level earning 85 points. Finally Sly picked up just 70 points from Ralf (5) because Ralf is so much lower level. Adding these all up we see that Sly earned a total of 234 points (79 + 85 + 70). We divide this by 3 to get Sly’s final experience point change, +78.

Now let’s see how JoeBoy fared. He lost to Sly, who was higher level. Again consulting row 4 of the table we look at the Lower Loss column to learn that JoeBoy lost 79 points. However, he also won against SueMe, who also happened to be a level higher. Row 2 of the chart shows us that a lower win earns 108 points. Finally, JoeBoy also picked up 85 experience points for beating Ralf. (Remember, Sly only got 70 for beating Ralf because their levels were further apart.) So JoeBoy earned a total of +38 experience points ((-79 + 108 + 85)/3) for his 2nd place finish.

Performing a similar calculation we see that SueMe lost 38 experience points ((-85 – 108 + 79)/3) and Ralf lost 78 experience points ((-70 – 85 – 79)/3).

Simple, see? Well, sort of. The above calculations hold up when all players are level 15 and above, but an extra consideration is made at lower levels. We give all low-level players a helping hand by reducing their point loss. Please consult the chart below.

Level >	Loss Factor >
1	0.00%
2	2.50%
3	5.00%
4	7.50%
5	10.00%
6	15.00%
7	20.00%
8	27.50%
9	35.00%
10	40.00%
11	45.00%
10	50.00%
11	55.00%
12	57.50%
13	60.00%
14	62.50%
15	65.00%
16	67.50%
17	70.00%
18	72.50%
19	75.00%
20	77.50%
21	80.00%
22	82.50%
23	85.00%
24	87.50%
25	90.00%
26	92.50%
27	95.00%
28	97.50%
29+	100.00%

This chart indicates a factor that we scale down point loss by. Remember the example above? JoeBoy gained points overall, but lost 79 to Sly. JoeBoy is level 7, so we multiply the 79 points lost by 0.2, resulting in just 15 points lost, making his new total +59 experience gained ((-15 + 108 + 85)/3) instead of his original +38.

SueMe lost 38 experience points according to the above calculations. If we use the loss factor for a player at level 8, however (0.275), this value changes. SueMe’s loss to Sly originally cost her 85 points, and her loss to JoeBoy cost her 108 points. We multiply 85 by 0.275 to get a new loss of 23 points vs. Sly, and 108 by 0.275 to get a new loss of 29 points vs. JoeBoy. SueMe’s new total experience change is +9 ((-23 – 29 + 79)/3) instead of the original -38. Quite a difference!

Ralf lost to everyone, but he’s just level 5 and much lower level than his opponents. 78 points lost is pretty severe. Instead when we apply a loss factor of 0.1 we see that Ralf lost just 7 experience points ((-7 – 8.5 – 7.9)/3) instead of -78, far less experience that he would have lost against a single opponent at his same level.

The final results of this game: Sly +78, JoeBoy +59, SueMe +9, and Ralf -7

If these players had all been 26 levels higher but retained the same level differentials the results would have been the original Sly +78, JoeBoy +38, SueMe -38, and Ralf -78, a net sum of zero. Between levels 30 and 40 the Halo 2 experience system is zero sum. Below level 31 it is obviously not zero sum (the above game resulted in a net +139 experience points added to the system) and therefore, in order to keep the system balanced, when you exceed level 40 your positive experience gain is scaled by the following factor to compensate:

Level	Win Factor
1-41	100%
42	95%
43	90%
44	85%
45	80%
46	70%
47	65%
48	60%
49	55%
50	50%

Special Considerations

You may be wondering what happens when you drop from a game before it’s over. This situation is actually quite simple. The game doesn’t forget about you. Instead you’re ranked in the final standings along with everyone else. However, when calculating the final standings all teams that had at least one player finish the game are ranked above all teams that dropped, regardless of score. Only then are teams sorted by final score, but within these two divisions, never crossing the line between finishers and droppers. So if your team drops you can still beat other teams that dropped, but you’ll always finish below teams that stuck it out until the end. Similarly, if you as a player drop but your team goes on to secure a glorious victory you’ll get just as much credit as your teammates that finished the game.

Let’s see, what have we forgotten? Do I get bonus points if I win when my team is a player down? Nope. What happens if I play a ranked game with a guest? Not allowed, guests can only play in unranked playlists and custom games. What if I get matched with a group of random players against a party that already knows each other?

Ah, that last one is a tricky question! Experience calculations do not take party size into account. However, mismatched parties are rare because our matchmaking system enforces party balance across teams. For example a party of 3 will not match against a party of 4 in the Team Skirmish playlist, and all games with parties of 3 or 4 in the Team Skirmish playlist must be balanced by an opposing party of the same size. There’s some flexibility to this system. For example, a party of 2 is not considered significant in the Team Skirmish playlist, and thus may be matched against random players that have been put on the same team. Also, when playing Big Team Battle games a party imbalance of 2 players is allowed, so a party of 3 or 4 may get matched against a party of 5. The chart below shows the minimum size party each playlist considers for party balancing (min big party), the max party size allowed in the playlist (max big party), and the allowed team imbalance.

Allowed Party Imbalance

Playlist	Min Big Party	Max Big Party	Max Party Imbalance
Rumble Pit	N/A	N/A	N/A
Team Skirmish	3	4	0
Head to Head	N/A	N/A	N/A
Big Team Battle	3	5	2
Minor Clan Match	3	4	0
Major Clan Match	6	8	2
Training Ground	N/A	N/A	N/A
Double Team	2	2	0
Team Preview	3	4	0

Alright, is that it? Almost. A few of the more astute among you have noticed that, at odd times, someone will be higher level than you are yet have less experience than you have. This can happen because experience and level are not completely wedded, as that chart we showed you earlier would lead you to believe. Instead, when you reach a new level for a matchmaking playlist we help you stay there, even when your experience points wouldn’t otherwise justify it. Basically you’ll stay at your current level, regardless of experience, until your experience drops below the midpoint experience required for the previous level.

This helps avoid the frustration of hovering right at the boundary between two levels, constantly switching back and forth. It also gives you a little peace of mind when you reach a new level because you know you won’t be slipping back down any time soon unless you have a really bad losing streak.

Web Stats vs. Game Stats

Although it often appears otherwise, Halo 2’s stats system is not directly tied to the Bungie.net web site. The web site includes a lot of info that it gets directly from the game, but all experience and level data reside on the Xbox Live stats servers. The level data shown on the web site is pulled from the Xbox Live servers, but this is a one-way transaction. As a result the stats information that you see on the web site is not guaranteed to be 100% accurate. If in doubt trust what’s shown in the game.

One Final Word

The goal of Halo 2’s level system is first and foremost to help you find the most enjoyable games possible. Games that are neck and neck, where the only sure way to win is by playing above your abilities, be it through better planning, more focus, improved team communication, whatever. But it’s fun to not be so serious all the time. That’s what custom games are for, or the Training Grounds playlist if you don’t have enough Friends online to form a custom game. But we believe that games that challenge you to rise above your current abilities are the most enjoyable and the most rewarding. Thus the level system is intended as a tool to help you find good games, not something to be abused or obsessed over. We’ve provided this detailed explanation of the system in order to take the mystery out of it, so that there’s complete transparency. Hopefully you’ll agree that it’s a fair and just system and you won’t worry too much about your level. Just play to get better and play to have fun, and in the process you’ll be doing your part to help the Halo 2 online community become bigger, stronger, more exciting and interesting, and most importantly an even friendlier place to play.