Author co-citation analysis

Author co-citation clustering finds groups of reference authors that tend to be cited together in papers. The clustering is accomplished by building a cooccurrence matrix of reference authors listing the number of common papers citing each pair of reference authors, i.e., an author cocitation matrix. Similarities based on these cocitation counts are used as proximities in the clustering routine. Such clustering tends to identify the groups of co-used authorities in the specialty. Normally, only highly cited reference aurhors are included in the analysis.

Loading the paper to reference author matrix

• Prior to author cocitation clustering, it is necessary to load the paper to reference author matrix from the database. To do this, on the TFGUI window select Matrix > load paper to ref author matrix. In the MATLAB command window, a few processing messges will appear, and a final message finished loading paper to ref author matrix.

Author co-citation clustering

• The paper to reference author matrix must be loaded into DIVA before author cocitation clustering can be performed. See the previous paragraph.
• In the TFGUI window, go to the Cooccurrence menu and select Use author co-ocitation default. The cooccur_gui will appear. The primary entity will be ref author and the secondary entity will be paper. This means that ref authors will be clustered on cooccurrence in papers.
• If the number of reference authors to cluster is greater than the number of clusters specified in coocur_gui, then DIVA will produce the number of clusters specified. Otherwise DIVA will produce clusters down to individual reference authors, whatever that number is.
• It is normally best to cluster down to individual reference authors, with number of reference authors between 50 to 200 depending on the size of the dataset. A good rule of thumb is to used 50 reference authors per 500 papers in the dataset.
• In author cocitation clustering the occurrence threshold corresponds to the minimum number of times cited. References authors cited more times than the occurrence threshold are retained.
• You should experiment with the occurence threshold to get close to the desired number of retained reference authors.
• Set the occurence threshold, click on Execute. An overwrite dialog will appear, click OK on this, then a dialog will appear telling the number of items (reference authors) that will be clustered, and asking whether to continue.
• If the number of items is too few, click NO and go back and reduce the coocurrence threshold, if too few, click NO and increase the threashold. If the number of items that will be clustered is close to the desired number, then click Yes and clustering will proceed.
• Clustering will proceed quickly, but simulated annealing to seriate the dendrogram may take very long if many items are to be clustered.

Go to Make RF to reference author crossmap