Possession

From Hattrick
Revision as of 03:53, 24 August 2007 by Aakholop (talk | contribs) (Reverted)

Introduction

When playing a match, the possession your team has at a certain minute determines your chances of getting a goal chance. It depends on both your team's and the opponent team's midfield.

Possession can be observed on the match report, at the end of the first half (minute 45) and the end of the second half (minute 90). That number is calculated using a formula which takes on consideration the midfield level of both the teams at that particular minute.

Formula

Possession(your_team) = 
100 * (Midfield_(your_team) / (Midfield_(your_team) + Midfield(opponents_team)) )
  • The scale of the midfields values is: 1=disastrous (very low), 2=disastrous (low) ...
  • It's also possible to use values: 0,00=disastrous (very low); 0,25=disastrous (low); 0,50=disastrous (high); 0,75=disastrous (very high); 1,00=wretched (very low) ...
  • You can test an implementation of the formula at The HattriX-Ray

Observation

One consequence of the formula (in terms of gameplay) is that as the average midfield level gets higher, possession differences get smaller for the same difference in midfield levels. For example:

  • disastrous (very low) vs wretched (very low) (1 level) = 71% possession
  • solid (very low) vs 'excellent (very low) (1 level) = 54%

Also, the midfield values used in the formula are the ones on that particular minute, while the midfield rating that is displayed at the end of the match is the average of the midfield during the 90 minutes. This explains the cases where discrepancies between the possession percentages at the 45th and 90th minute and the midfield rating seem to appear. Events such as:

  • red cards (to players affecting the midfield)
  • injuries (to players affecting the midfield)
  • weather non-goal events (to players affecting the midfield)
  • confusion

affect the midfield from the time the event is reported, hence affecting the possession as well.

Player stamina may alter possession minute-to-minute, if a player affecting the midfield is below excellent stamina, but this will not produce an event in the match report.

Additional factors that affect midfield ratings uniformly throughout the match include:

Other

Possession vs goal opportunities nonlinearity

The following contents are based on experience and/or research conducted by Hattrick users — which means that their veracity and accuracy have not been confirmed by any official statement, and consequently they do not necessarily reflect the game reality. Please take this into consideration!


Statistical analysis over the goal opportunities distribution taking into consideration the possession levels suggest that the relation between the possession and the number of chances your team has is far from being 1:1. The numbers suggest that you will most likely get 9 or 10 chances in the game if you have 65% possession.

  • When you have 54% possession, you will most likely get 6 out of 10 chances.
  • When you have 57% possession, you will most likely get 7 out of 10 chances.
  • When you have 62% possession, you will most likely get 8 out of 10 chances.

(please insert the appropiate explanation and links here)

Although this nonlinearity is widely believed, HT-Hasse is on record with a conference post stating that the chance a team will get a scoring chance at a particular point in the match is exactly equal to their possession percentage. Although this averages to 62% of chances for 62% possession, the distribution is more complicated than that.

For example, for 60% possession, this chance distribution would result in the team getting 4 chances 11% of the time, 5 chances 20% of the time, 6 chances 25% of the time, 7 chances 20% of the time, and 8 chances 12% of the time. Although six chances is the most likely outcome, it is more likely that the team with 60% possession will get seven or more than that they will get six. Outcomes with less than six chances make up about 36% of all outcomes, outcomes with six chances makes up 25% of all outcomes, and more than 6 chances make up the remaining 38%.

Keywords: possession chance

By: HT-Hasse 2237636.31 as reply to 2237636.30
To: Jazz23 25/12/2004 at 23.17
If it is a normal chance a team with 54% posession has 54% chance of getting it.

Later he added:

Keywords: possession chance

By: HT-Hasse 2237636.48 as reply to 2237636.47
To: el-insaciable 25/12/2004 at 23:55
Actually your statement in this thread made me wonder... When it's calculated which team will get a chance, is there a randomfactor which decides how great the chance is? Or is it only the ratings (with an amount of random too) which has an influence?

I don't know exactly how that works, and I don't want to know too much. It would spoil the fun of the game for me.


First message from HT-Hasse in this thread

Keywords: possession chance

By: HT-Hasse 2237636.13 as reply to 2237636.9
To: Jazz23 25/12/2004 at 22:31
No I want 56% to be 56%!!! That should be 5 chances for one and 4 for other team... not always but average in 100 or 1000 games should be that! 'Couse now team with 56% gets about 75% of chances...

No. On average a team with 56% posession does get 56% of the chances. But you forget that not all chances are reported. The chance has to be good enough to be presented in the match report.

Later he refused to argue and posted 2237636.48.