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David Houchens

USATT#: 93225

Introduction
This page explains how David Houchens (USATT# 93225)'s rating went from 1145 to 1266 at the Kansas City Table Tennis event from 2 Feb 2019. These ratings are calculated by the ratings processor which goes through 4 passes over the match results data for a league event. The following values are produced at the end of each of the 4 passes of the ratings processor for David Houchens for this league event.

Initial Rating Pass 1 Pass 2 Pass 3 Final Rating (Pass 4)
1145 1250 1145 1184 1266


You can click here to view a table of all the resultant values from each of the 4 passes (and the initial rating) of the ratings processor for all of the 11 players in this league event. Sections below for further details on the initial rating and the 4 passes of the ratings processor.

Note: We use mathematical notation to express the exact operations carried out in each pass of the ratings processor below. Whenever you see a variable/symbol such as for example Xi3, we are following the convention that the superscript part of the variable (in this case "3") indicates an index (such as in a series), and it should not be misconstrued to be an exponent (which is how it is used by default).

Initial Rating
The initial rating of a player for a league event is the rating the player received at the end of the most recent league event prior to the current league event. If this is the first league event the player has ever participated in (based on our records), then the player has no initial rating.

The initial rating for Kansas City Table Tennis event from 2 Feb 2019 for David Houchens, and its source league event are as follows:
Initial Rating From League Event Date
1145 Kansas City Table Tennis 19 Jan 2019

Click here to view the details of the initial ratings for all the players in this league event.

Pass 1 Rating
In Pass 1, we only consider all the players that come into this league event with an initial rating while ignoring all the unrated players. If a rated player has a match against an unrated player, then that match result is ignored from the pass 1 calculations as well. We apply the point exchange table shown below to all the matches participated in by the rated players:

Point Spread Expected Result Upset Result
0 - 12 8 8
13 - 37 7 10
38 - 62 6 13
63 - 87 5 16
88 - 112 4 20
113 - 137 3 25
138 - 162 2 30
163 - 187 2 35
188 - 212 1 40
213 - 237 1 45
238 and up 0 50

Suppose player A has an initial rating of 2000 and player B has an initial rating of 2064, and they played a match against each other. When computing the impact of this match on their rating, the "Point Spread" (as it is referred to in the table above) between these two players is the absolute value of the difference their initial ratings. When the player with the higher rating wins, presumably the better player won, which is the expected outcome of a match, and therefore the "Expected Result" column applies. If the player with the lower rating wins the match, then presumably this is not expected, and therfore it is deemed as an "Upset Result" and the value from that column in the table above is used. So, in our example of player A vs player B, if player B wins the watch, then the expected outcome happens, and 5 points are added to player B's rating and 5 points are deducted from player A's rating. Looking at David Houchens's match results and applying the point exchange table, gives us the following result:

David Houchens's Wins
Winner Loser
Point Spread Outcome Gain Player USATT # Rating Player USATT # Rating
225 UPSET 45 David Houchens 93225 1145 Brian Xiong 198943 1370
412 EXPECTED 0 David Houchens 93225 1145 Will Mbugua 256531 733
0 0 David Houchens 93225 0 Cindy Westervelt 256691 0
38 UPSET 13 David Houchens 93225 1145 Dennis R. Sulltrop 48389 1183
7 UPSET 8 David Houchens 93225 1145 Jim Heney 256556 1152
40 UPSET 13 David Houchens 93225 1145 Daniel Posch 30072 1185
52 UPSET 13 David Houchens 93225 1145 Lih Chen 213164 1197
43 UPSET 13 David Houchens 93225 1145 Peter Chu 250336 1188

David Houchens's Losses
Winner Loser
Point Spread Outcome Loss Player USATT # Rating Player USATT # Rating

You can click here to view a table of outcomes and points gained/lost from all the matches with all the players in this league event.

The "Outcome" column above, shows whether the match had an expected (player with the higher rating wins the match) or an upset (player with the higher rating loses the match) outcome. Based on this outcome, and using both the player's initial rating, we apply the point exchange table from above and show the ratings points earned and lost by David Houchens in the "Gain" column. Matches are separated out into two tables for wins and losses where points are gained and lost respectively. We get the following math to calculate the Pass 1 Rating for David Houchens:

Initial Rating Gains/Losses Pass 1 Rating
1145 + 45 + 0 + 0 + 13 + 8 + 13 + 13 + 13 =1250

You can click here to view a table of pass1 calculations for all the rated players in this league event.

Pass 2 Rating
The purpose of this pass is solely to determine ratings for unrated players. To do this, we first look at the ratings for rated players that came out of Pass 1 to determine an “Pass 2 Adjustment”. The logic for this is as follows:

  1. We calculate the points gained in Pass 1. Points gained is simply the difference between the Pass 1 Rating and the Initial Rating of a player:

    ρi2 = Pi1 - Pi0
    where,

    Symbol Universe Description
    Pi0 Pi0+ the initial rating for the i-th player. We use the symbol P and the superscript 0 to represent the idea that we sometimes refer to the process of identifying the initial rating of the given player as Pass 0 of the ratings processor.
    Pi1 Pi1+ the Pass 1 rating for the i-th player.
    ρi2 ρi2 the points gained by the i-th player in this league event. Note here that we use the superscript 2 to denote that this value is calculated and used in Pass 2 of the ratings processor. Further, ρi2 only exists for players who have a well defined Pass 1 Rating. For Players with an undefined Pass 1 Rating (unrated players), will have an undefined ρi2.
    i i[1,11] the index of the player under consideration. i can be as small as 1 or as large as 11 for this league event and the i-th player must be a rated player.

  2. For rated players, Pass 1 points gained, ρi2, is used to calculate the Pass 2 Adjustment in the following way:
    1. If a player gained less than 50 points (exclusive) in pass 1, then we set that player's Pass 2 Adjustment to his/her Initial Rating.
    2. If a player gained between 50 and 74 (inclusive) points in pass 1, then we set the player's Pass 2 Adjustment to his/her Final Pass1 Rating.
    3. If a player gains 75 or more points (inclusive) in pass 1, then the following formula applies:
      • If the player has won at least one match, and lost at least 1 match in the league event, then the player's Pass 2 Adjustment is the average of his/her Final Pass 1 Rating and the average of his/her opponents rating from the best win and the worst loss, represented using the formula below:

        αi2 = Pi1 + Bi + Wi 2 2

        where αi2 is the Pass 2 Adjustment for the current player, Pi1 is the Pass 1 Rating, Bi is the rating of the highest rated opponent against which the current player won a match, and Wi is the rating of the lowest rated opponent against which the current player lost a match.
      • If a player has not lost any of his/her matches in the current league event, the mathematical median (rounded down to the nearest integer) of all of the player's opponents initial rating is used as his/her Pass 2 Adjustment:

        αi2 = {Pk0}

        where Pk0 is the initial rating of the player who was the i-th player's opponent from the k-th match.
        Symbol Universe Description
        i i[1,11] the index of the player under consideration. i can be as small as 1 or as large as 11 for this league event and the i-th player must be a rated player.
        q q[1,36] the index of the match result under consideration. q can be as small as 1 or as large as 36 for this league event and the q-th match must be have both rated players as opponents.
        g g[1,5] the g-th game of the current match result under consideration. q can be as small as 1 or as large as 5 for this league event assuming players play up to 5 games in a match.
        Pk0 Pk0+ initial rating of the i-th player's opponent from the k-th match.


      • Therefore, the Pass 2 Adjustment for David Houchens is calculated as follows:
        • Given the initial rating of 1145,
        • and the Pass 1 rating of 1250,
        • the Pass 1 gain is 1250 - 1145 = 105.
        • Since the Pass 1 Gain of 105 is greater than 74, and David Houchens has won all matches, the Pass 2 Rating (also referred to as Pass 2 Adjustment) set to be the mathematical median of all of his opponents initial ratings. His opponents initial ratings are 733, 1152, 1183, 1185, 1188, 1197, 1370 and their median (rounded down) is 1185.

        You can click here to view a table of Pass 2 Adjustments for all the rated players in this league event.

  3. After calculating the Pass 2 Adjustment for all the rated players as described above, we can now calculate the Pass 2 Rating for all the unrated players in this league event (which is the main purpose of Pass 2). Pass 2 Rating is calculated using the following formula:
    1. If all of the matches of an unrated player are against other unrated players, then the Pass 2 Rating for that player is simply set to 1200. You can click here to view these players who received a 1200 Pass 2 Rating. Not all of David Houchens's matches were against unrated players. So this rule does not apply to him.
    2. For unrated players with wins and losses, where at least 1 of the opponents has an initial rating, the Pass 2 Rating is the average of the best win and the worst loss (using the Pass 2 Adjustment of all rated players) as defined by this formula here:

      Pi2 = Bi2 + Wi2 2

      where Pi2 is the Pass 2 Rating for the i-th player, Bi2 is the largest Pass 2 Adjustment (best win) of the opponenet against whom the i-th player won a match, and Wi2 is the smallest Pass 2 Adjustment (worst loss) of the opponent against whom the i-th player lost a match.
    3. For unrated players with all wins and no losses, where at least 1 of the opponents has an initial rating, the Pass 2 Rating is calculated using the following formula:
      Pi2 = Bi2 + k=0Mi-1 I(Bi2-αk2)
      where the function I(x) is defined as, \begin{equation} I(x)=\left\{ \begin{array}{ll} 10, & \text{if}\ x >= 1, x <= 50 \\ 5, & \text{if}\ x >= 51, x <=100 \\ 1, & \text{if}\ x >= 101, x <= 150 \\ 0, & \text{otherwise} \end{array}\right. \end{equation}
      where,
      Symbol Universe Description
      Pi2 Pi2+ the pass 2 rating, of the i-th player in this league event only applicable to unrated players, where Pi0 is not defined
      Bi2 Bi2+ the largest of the Pass 2 Adjustments of opponents of the i-th player against whom he/she won a match.
      αk2 αk2+ the Pass 2 Adjustment of the player who was the opponent of the i-th player in the k-th match
      I(x) I:+ a function that maps all integers to one of the values from -- 0, 1, 5, 10.
      Mi Mi+ total number of matches played by the i-th player in this league event
      k k[0,Mi-1]+ The index of the match of the i-th player ranging from 0 to Mi-1
    4. For unrated players with all losses and no wins, where at least 1 of the opponents has an initial rating, the Pass 2 Rating is calculated using the following formula:
      Pi2 = Wi2 + k=0Mi-1 I(Wi2-αk2)
      where I(x) is defined above and,

      Symbol Universe Description
      Pi2 Pi2+ the pass 2 rating, of the i-th player in this league event only applicable to unrated players, where Pi0 is not defined
      Wi2 Wi2+ the smallest of the Pass 2 Adjustments of opponents of the i-th player against whom he/she lost a match.
      αk2 αk2+ the Pass 2 Adjustment of the player who was the opponent of the i-th player in the k-th match
      I(x) I:+ a function that maps all integers to one of the values from -- 0, 1, 5, 10.
      Mi Mi+ total number of matches played by the i-th player in this league event
      k k[0,Mi-1]+ The index of the match of the i-th player ranging from 0 to Mi-1
    5. For the rated players, all the work done in Pass 1 and Pass 2 to undone and they have their ratings reset back to their initial ratings while the unrated players keep their Pass 2 Adjustment as their final Pass 2 Rating. Since David Houchens is a rated player, his Pass 2 Adjustment of 1185 will be ignored, along with him Pass 1 Rating of 1250 and his Pass 2 Rating will be set to his initial rating of 1145 with which he came into this league event.


Click here to see detailed information about the Pass 2 Ratings of all the other players in this league event.

Pass 3 Rating
Any of the unrated players who have all wins or all losses are skipped in Pass 3. Since David Houchens has an initial rating of 1145, he is not an unrated player, and therefore this rule does not apply to him. You can click here to view list of all the players that are skipped in this Pass 3.

Pass 3 Rating is calculated using 2 steps described below:
  1. In the first part of Pass 3, we apply the point exchange table described in Pass 1 above except this time by using all the players' Pass 2 Ratings. Looking at David Houchens's wins and losses and applying the point exchange table, gives us the following result:
    David Houchens's Wins
    Winner Loser
    Point Spread Outcome Gain Player USATT # Rating Player USATT # Rating
    225 UPSET 45 David Houchens 93225 1145 Brian Xiong 198943 1370
    412 EXPECTED 0 David Houchens 93225 1145 Will Mbugua 256531 733
    0 0 David Houchens 93225 0 Cindy Westervelt 256691 0
    38 UPSET 13 David Houchens 93225 1145 Dennis R. Sulltrop 48389 1183
    7 UPSET 8 David Houchens 93225 1145 Jim Heney 256556 1152
    40 UPSET 13 David Houchens 93225 1145 Daniel Posch 30072 1185
    52 UPSET 13 David Houchens 93225 1145 Lih Chen 213164 1197
    43 UPSET 13 David Houchens 93225 1145 Peter Chu 250336 1188

    David Houchens's Losses
    Winner Loser
    Point Spread Outcome Loss Player USATT # Rating Player USATT # Rating

    You can click here to view a table of outcomes and points gained/lost from all the matches with all the players in this league event for Pass 3 Part 1.

    The "Outcome" column above, shows whether the match had an expected (player with the higher rating wins the match) or an upset (player with the higher rating loses the match) outcome. Based on this outcome, and using both the player's Pass 2 Rating, we apply the point exchange table from above and show the rating points earned and lost by David Houchens in the "Gain" column. Matches are divided up into two tables for wins and losses where points are "Gain"ed for the wins and "loss"ed for losses. Putting all the gains and losses together, we get the following math to calculate the rating for David Houchens in this first part of Pass 3:

    Pass 2 Rating Gains/Losses Pass 3 Part 1 Rating
    1145 + 45 + 0 + 0 + 13 + 8 + 13 + 13 + 13 =1250


    You can click here to view a table of these calculations for all the players in this league event.

  2. Given the Pass 3 Part 1 rating calculated above, the second part of Pass 3 looks very similar to the part of Pass 2 that deals with rated players where we calculate their Pass 2 Adjustment.
    1. First, we calculate the points gained in Pass 3 Part 1. Points gained is simply the difference between the Pass 3 Part 1 Rating and the Pass 2 Rating of a player:

      ρi3 = pi3 - Pi2
      where,

      Symbol Universe Description
      Pi2 Pi2+ the Pass 2 Rating for the i-th player.
      pi3 pi3+ the Pass 3 Part 1 rating for the i-th player. (Note that since this is an intermediate result, we are using a lower case p instead of the upper case P that we use to indicate final result from each pass of the ratings processor.
      ρi3 ρi3 the points gained by the i-th player in this league event in Pass 3.
      i i[1,11] the index of the player under consideration. i can be as small as 1 or as large as 11 for this league event.

  3. Pass 3 points gained, ρi3, is then used to calculate the Pass 3 Part 2 Rating in the following way:
    1. If a player gained less than 50 points (exclusive) in Pass 3 Part 1, then we set that player's Pass 3 Part 2 Rating to his/her Pass 2 Rating.
    2. If a player gained between 50 and 74 (inclusive) points in Pass 3 Part 1, then we set the player's Pass 3 Part 2 Rating to his/her Pass 3 Part 1 Rating.
    3. If a player gains 75 or more points (inclusive) in Pass 3 Part 1, then the following formula applies:
      • If the player has won at least one match, and lost at least 1 match in the league event, then the player's Pass 3 Part 2 Rating is the average of his/her Pass 3 Part 1 Rating and the average of his/her opponents rating from the best win and the worst loss, represented using the formula below:

        αi3 = pi3 + Bi3 + Wi3 2 2

        where αi3 is the Pass 3 Part 2 Rating for the current player, pi3 is the Pass 3 Part 1 Rating, Bi3 is the rating of the highest rated opponent against which the current player won a match, and Wi is the rating of the lowest rated opponent against which the current player lost a match.
      • If a player has not lost any of his/her matches in the current league event, the mathematical median (rounded down to the nearest integer) of all of the player's opponents rating is used as his/her Pass 3 Part 2 Rating:
        αi3 = {pk3}

        where pk3 is the Pass 3 Part 1 Rating of the i-th player's opponent from the k-th match.

      • Therefore, the Pass 3 Part 2 Rating for David Houchens is calculated as follows:
        • Given the Pass 2 Rating of 1145,
        • and the Pass 3 Part 1 rating of 1250,
        • the Pass 3 Part 1 gain is 1250 - 1145 = 105.
        • Since the Pass 3 Gain of 105 is greater than 74, and David Houchens has won all matches, the Pass 3 Rating (also referred to as Pass 3 Adjustment) is set to be the the mathematical median (rounded down) of all of his opponents Pass 3 Rating. His opponents Pass 2 ratings are 733, 1122, 1152, 1183, 1185, 1188, 1197, 1370, and their median (rounded down) is 1184.

      The Pass 3 Part 2 rating ends up becoming the final Pass 3 rating (also referred to as the Pass 3 Adjustment) except as follows:
      • In the cases where the Pass 3 Part 2 rating is less than the players' initial rating Pi0, the Pass 3 rating is reset back to that players initial rating. David Houchens's Pass 3 Part 2 Rating came out to 1184. Since this value is greater than David Houchens's initial rating of 1145, his Pass 3 Adjustment is set to his Pass 3 Part 2 Rating of 1184.

      • It is possible for the admin of this league event to override the Pass 3 Adjustment calculated above with a value they deem appropriate. David Houchens does not have a manually overridden value for his Pass 3 Adjustment, therefore the value remains at 1184.
      You can click here to view a table of Pass 3 Part 2 Ratings for all the players in this league event along with any manually overridden values.

Pass 4 Rating
Pass 4 is the final pass of the ratings processor. In this pass, we take the adjusted ratings (Pass 3 Adjustment) of all the rated players, and the assigned rating of unrated players (Pass 2 Rating), and apply the point exchange table to the match results based on these ratings to arrive at a final rating. Looking at David Houchens's match results and applying the point exchange table, gives us the following result:

David Houchens's Wins
Winner Loser
Point Spread Outcome Gain Player USATT # Rating Player USATT # Rating
186 UPSET 35 David Houchens 93225 1184 Brian Xiong 198943 1370
451 EXPECTED 0 David Houchens 93225 1184 Will Mbugua 256531 733
62 EXPECTED 6 David Houchens 93225 1184 Cindy Westervelt 256691 1122
1 EXPECTED 8 David Houchens 93225 1184 Dennis R. Sulltrop 48389 1183
32 EXPECTED 7 David Houchens 93225 1184 Jim Heney 256556 1152
1 UPSET 8 David Houchens 93225 1184 Daniel Posch 30072 1185
13 UPSET 10 David Houchens 93225 1184 Lih Chen 213164 1197
4 UPSET 8 David Houchens 93225 1184 Peter Chu 250336 1188

David Houchens's Losses
Winner Loser
Point Spread Outcome Loss Player USATT # Rating Player USATT # Rating

You can click here to view a table of outcomes and points gained/lost from all the matches with all the players in this league event.

The "Outcome" column above, shows whether the match had an expected (player with the higher rating wins the match) or an upset (player with the higher rating loses the match) outcome. Based on this outcome, and using both the players' Pass 3 Adjustment, we apply the point exchange table from above and show the ratings points earned and lost by David Houchens in the "Gain" and "Loss" columns. Matches are separated out into two tables for wins and losses where points are gained and lost respectively. We get the following math to calculate the Pass 4 Rating for David Houchens:

Pass 3 Rating Gains/Losses Pass 4 Rating
1184 + 35 + 0 + 6 + 8 + 7 + 8 + 10 + 8 =1266

You can click here to view a table of Pass 4 calculations for all the players in this league event.