PlanetsCentral

This page briefly describes the ranking system used by PlanetsCentral.

Your rank is determined by three values:

• your skill. You receive skill points for every game you finish.
• your reliability. Only reliable players can reach high ranks.
• your experience. You need to play a specific number of turns to reach a rank.

These values determine your rank:

Skill

You gain skill points for every game you finish. The amount you get depends on your position, the game difficulty, the ranks of your opponents (a Spaceman winning against an Admiral gets more points than the other way around), your reliability for this very game, and the length of the game (games shorter than 50 turns get you fewer points).

New_skill_points =
    100 * Position_points
        * Game_difficulty
        * Rank_difficulty
        * Reliabity_rate
        * Turn_factor

Position_points =
    Table_value * (Num_players / 11)

Game_difficulty =
    (1.0 for normal game, >1 for harder games; see here)

Rank_difficulty =
    (Sum(Ranks_of_beaten_opponents) + 110)/(Own_rank * No_of_opponents + 110)

Reliability_rate =
    (Submitted_turns / Total_turns)^2

Turn_factor =
    min(Total_turns / 50, 1)

Reliability

Reliability is expressed as a number between 0 and 100. This value expresses your current reliability. If you submit turns, your reliability will approach 100. If you miss turns, your reliability will drop. If you drop from a game, your reliability will drop, depending on your position in the game (i.e. if you leave an almost-dead empire, there will be just a slight penalty; if you leave an active game in the middle, the penalty will be bigger).

Formulas for turn submission:

New_reliability =
    Old_reliability * (100 - Speed) / 100 + New_points * Speed

New_points =
    1.0      if turn submitted
    0.0      if turn missed
    0.5      if your replacement missed the turn
    0.75     if your replacement's replacement missed the turn

Speed =
    3.0      (configuration option)

Formula for dropping from a game:

New_reliability =
    Old_reliability * (1 - Your_score / Score_of_best_player_in_game)

Note that the Reliability is not an absolute turn submission rate. It will track your current turn submission rate. If you used to be a very reliable player, but start missing turns, it will drop. Likewise, if you used to be a lousy player but start getting serious, it will rise. It will slowly "forget" yesterday's sins (at the speed set by the Speed configuration option).

Also note that if your reliability drops too far below the requirement for your current rank, you will be demoted.

Colophon

This ranking system is heavily based upon the PlanetsServer ranking system. Actually, the rank names and levels are the same. The reliability is computed differently, though.

The game difficulty formula uses the Vagabond's VPI computation as the Production rating.