Table 2.

Measure . | Formula . |
---|---|

p_multi | The percentage of multi-assigned journals |

p_outside | The percentage of journals that are classified in more than one research area |

pro | ∑_{k≠i}c_{ik}/∑_{j}c_{ij} |

d_links | The number of links between different SCs established by journals in a given category |

Pratt index | $2n+12\u2212\u2211kgpikn\u22121$, where g is the index obtained by ranking p_{ik} in decreasing order |

Spec | ∑_{k}$cik2$/(∑_{k}c_{ik})^{2} |

Simpson index | 1 − ∑_{k}$pik2$ |

Shannon entropy | −∑_{k}p_{ik} lnp_{ik} |

Brillouin index | (log(∑_{k}c_{ik})! − ∑_{k} log c_{ik}!)/∑_{k}c_{ik} |

Gini coefficient | $\u2211k2h\u2212n\u22121cikn\u2211kcik$, where h is the index attained by sorting SCs according to c_{ik} in increasing order |

RS | ∑_{j.k}(1 − s_{jk})p_{ij}p_{ik} |

Hill-type measure | 1/∑_{j.k}s_{jk}p_{ij}p_{ik} |

Coherence | ∑_{j,k}$cjki$(1 − s_{jk}) |

BC^{1} | ∑_{j,k}$rjikrjk$ |

CC | ∑_{j}P_{j}$cijaiaj$ |

AS | ∑_{i}P_{i} ($1N$∑_{j}s_{ij}), where N is the number of all other SCs |

Measure . | Formula . |
---|---|

p_multi | The percentage of multi-assigned journals |

p_outside | The percentage of journals that are classified in more than one research area |

pro | ∑_{k≠i}c_{ik}/∑_{j}c_{ij} |

d_links | The number of links between different SCs established by journals in a given category |

Pratt index | $2n+12\u2212\u2211kgpikn\u22121$, where g is the index obtained by ranking p_{ik} in decreasing order |

Spec | ∑_{k}$cik2$/(∑_{k}c_{ik})^{2} |

Simpson index | 1 − ∑_{k}$pik2$ |

Shannon entropy | −∑_{k}p_{ik} lnp_{ik} |

Brillouin index | (log(∑_{k}c_{ik})! − ∑_{k} log c_{ik}!)/∑_{k}c_{ik} |

Gini coefficient | $\u2211k2h\u2212n\u22121cikn\u2211kcik$, where h is the index attained by sorting SCs according to c_{ik} in increasing order |

RS | ∑_{j.k}(1 − s_{jk})p_{ij}p_{ik} |

Hill-type measure | 1/∑_{j.k}s_{jk}p_{ij}p_{ik} |

Coherence | ∑_{j,k}$cjki$(1 − s_{jk}) |

BC^{1} | ∑_{j,k}$rjikrjk$ |

CC | ∑_{j}P_{j}$cijaiaj$ |

AS | ∑_{i}P_{i} ($1N$∑_{j}s_{ij}), where N is the number of all other SCs |

^{1}Leydesdorff (2007) used a symmetrical cosine matrix instead of a citation matrix to measure the interdisciplinarity of journals using BC. He claimed that the size of journals was “controlled” in this way. However, some researchers still use a citation matrix to measure BC (for instance Silva et al., 2013). In our view, it is more intuitive to use a citation matrix as input for BC, as it better demonstrates the concept of intermediation. Hence, we use a citation matrix in the present study. The shortest path indicates the path with the lowest total edge weight. However, in our case, results obtained by BC can be scaled with size (i.e. if SC *i* has a large number of publications, it is likely to have a high degree of interdisciplinarity when BC is used). BC was calculated using the R package SNA: Tools for social network analysis. The input citation matrix was generated using SQL from the in-house WoS database at CWTS. Other measures were calculated using SQL or a combination of SQL and R.

This site uses cookies. By continuing to use our website, you are agreeing to our privacy policy.