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Zachary's karate club

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The Zachary Karate Club is a well-known social network of a university karate club described in "An Information Flow Model for Conflict and Fission in Small Groups" paper by Wayne W. Zachary.

Contents

Network description

A social network of a karate club was studied by Wayne W. Zachary for a period of three years from 1970 to 1972. The network captures 34 members of a karate club, documenting 78 pairwise links between members who interacted outside the club. During the study a conflict arose between the administrator "John A" and instructor "Mr. Hi" (pseudonyms), which led to the split of the club into two. Half of the members formed a new club around Mr. Hi, members from the other part found a new instructor or gave up karate. Basing on collected data Zachary assigned correctly all but one member of the club to the groups they actually joined after the split.

Zachary's methodology

Before the split each side tried to recruit adherents of another party. Thus, communication flow had a special importance and the initial group would likely split at the "borders" of the network. Zachary used the maximum flow – minimum cut Ford–Fulkerson algorithm from “source” Mr. Hi to “sink” John A: the cut closest to Mr. Hi that cuts saturated edges divides the network into the two factions. Zachary correctly predicted each member's decision except member #9, who went with Mr. Hi instead of John A.

Data set

The data set for Zachary's karate club is in open access on the internet. The data can be summarized as list of integer pairs. Each integer represents one karate club member and a pair indicates the two members interacted. The data set is summarized below and also in the adjoining image. Node 1 stands for the instructor, node 34 for the club administrator / president.

[2 1] [3 1] [3 2] [4 1] [4 2] [4 3] [5 1] [6 1] [7 1] [7 5] [7 6] [8 1] [8 2] [8 3] [8 4] [9 1] [9 3] [10 3] [11 1] [11 5] [11 6] [12 1] [13 1] [13 4] [14 1] [14 2] [14 3] [14 4] [17 6] [17 7] [18 1] [18 2] [20 1] [20 2] [22 1] [22 2] [26 24] [26 25] [28 3] [28 24] [28 25] [29 3] [30 24] [30 27] [31 2] [31 9] [32 1] [32 25] [32 26] [32 29] [33 3] [33 9] [33 15] [33 16] [33 19] [33 21] [33 23] [33 24] [33 30] [33 31] [33 32] [34 9] [34 10] [34 14] [34 15] [34 16] [34 19] [34 20] [34 21] [34 23] [34 24] [34 27] [34 28] [34 29] [34 30] [34 31] [34 32] [34 33]

Zachary Karate Club Club

Zachary Karate Club Club is a honorific group that awards membership in the group, along with a traveling trophy, to a scientist who is the first to use Zachary's Karate Club as an example at a conference on networks. The first scientist to be awarded was Cristopher Moore in 2013.

ZKCC Trophy Recipients

  • 11th Federico Battiston (September 2016)
  • 10th Giona Casiraghi (July 2016)
  • 9th Filippo Radicchi (May 2016)
  • 8th Qing Ke (September 2015)
  • 7th Manlio De Domenico (July 2015)
  • 6th Tiago Peixoto (June 2015)
  • 5th Mark Newman (June 2014)
  • 4th Marián Boguñá (September 2013)
  • 3th YY Ahn (July 2013)
  • 2nd Mason Porter (June 2013)
  • 1st Cristopher Moore (May 2013)
  • References

    Zachary's karate club Wikipedia