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Build a co-citation network

Source: R/network-cocitation.R
sm_network_cocitation.Rd

Constructs an undirected co-citation network. Two works (A and B) are connected by an edge if they are both cited by a common third work. The edge weight equals the number of works that co-cite A and B.

Usage

sm_network_cocitation(corpus, min_weight = 2L, call = rlang::caller_env())

Arguments

corpus

An sm_corpus object with a populated references table.

min_weight

Integer; minimum co-citation count to retain an edge. Defaults to 2L to reduce noise.

call

Caller environment for error reporting.

Value

A tidygraph::tbl_graph object (undirected). Nodes carry name (work ID) and columns from corpus$works. Edges carry a weight column representing co-citation frequency.

Details

The algorithm:

  1. For every citing work, enumerate all pairs of cited works.

  2. Count how often each pair co-occurs.

  3. Filter by min_weight.

Empty input (zero works, zero references, or no pairs above the threshold) returns an empty undirected tbl_graph.

See also

Other networks: sm_network_citation(), sm_network_collab(), sm_network_coupling(), sm_network_coword(), sm_network_semantic()

Examples

corpus <- sm_example_corpus()
g <- sm_network_cocitation(corpus, min_weight = 2L)
g
#> # A tbl_graph: 198 nodes and 2289 edges
#> #
#> # A bipartite simple graph with 1 component
#> #
#> # Node Data: 198 × 16 (active)
#>    name      doi   title abstract  year type  source_id cited_by_count oa_status
#>    <chr>     <chr> <chr> <chr>    <int> <chr> <chr>              <int> <chr>    
#>  1 W0000000… 10.1… Tumo… This st…  2023 jour… S0000000…              3 green    
#>  2 W0000000… 10.1… Biom… This st…  2020 jour… S0000000…              9 hybrid   
#>  3 W0000000… 10.1… Colo… This st…  2024 jour… S0000000…             28 green    
#>  4 W0000000… 10.1… Tumo… This st…  2020 revi… S0000000…             29 green    
#>  5 W0000000… 10.1… Clin… This st…  2020 jour… S0000000…             16 hybrid   
#>  6 W0000000… 10.1… Tumo… This st…  2018 jour… S0000000…             16 closed   
#>  7 W0000000… 10.1… Sing… This st…  2021 lett… S0000000…             26 bronze   
#>  8 W0000000… 10.1… Colo… This st…  2020 jour… S0000000…              7 hybrid   
#>  9 W0000000… 10.1… Gene… This st…  2024 revi… S0000000…              6 gold     
#> 10 W0000000… 10.1… Colo… This st…  2019 revi… S0000000…              5 gold     
#> # ℹ 188 more rows
#> # ℹ 7 more variables: language <chr>, pmid <chr>, arxiv_id <chr>,
#> #   openalex_id <chr>, is_retracted <lgl>, retraction_date <date>,
#> #   last_refreshed <dttm>
#> #
#> # Edge Data: 2,289 × 3
#>    from    to weight
#>   <int> <int>  <int>
#> 1     1     7      3
#> 2     1     9      2
#> 3     1    10      2
#> # ℹ 2,286 more rows