Recent changes to documentationThis page lists changes in ranking procedures since the last version of the documentation was released in July 2012.
- An error was discovered that put excessive weight on the proportion of the work of some authors in particular NEP fields. The error is corrected and documented weights are applied since the March 2013 rankings. Less than 50 authors were affected, and only for the field rankings.
- With the June 2013 ranking, the citation breadth criterion NEPCites has been introduced for authors only. It count in how many NEP fields papers were disseminated that cited the author's works. Ties are resolved by looking at the same, but counting the fields with at least x papers, where x is the iteger part of the previous score divided by 10, plus two.
- With the June 2013 ranking, the strength of students criterion is added to all aggregate rankings. It uses data collected at the RePEc Genealogy. For authors, insttutions and regions, data on students are aggregated like they aggregated for institution rankings (i.e., add score for each criterion, then rank each, then take harmonic mean of ranks, leaving out best and worst). When a student has two advisors, each gets half the student;s scores.
- In October 2013, we introduced rankings that are based on the last 10 years of publications for journals, series, authors, institutions and regions. At the moment, these rankings are not computed within fields and regions, as the small samples make them less reliable.
- In June 2014, we have adjusted the way the recursive and discounted recursive impact factors were used for weighting article pages, documents, and citations. A scaling factor was previously applied twice instead of once. The correction does not affect the rankings in any way, but it allows authors to replicate their scores. New scores are 21.4 times higher.
- In June 2014, we have started preventing republished articles from counting in the impact factors of the republishing journal. Also, these articles are dropped from the list of top recent works.
- In November 2015, we started not counting any items older than 1970 in the calculation of impact factors. Including them would penalize publishers that provide older material, as we are less likely to find citations for those old items.
- For the December 2016 ranking, we introduced the Euclidian measure of citations, following the article of Perry and Reny, with one small change: we adjust citation counts for citation frequency in the field of the citing paper, not the cited paper. This ranking does not count towards the aggregate ranking until further notice.
- With the May 2017 ranking, the Euclidian score counts towards aggregate rankings. Also, the top and bottom two scores are dropped from the calculations, instead of top and bottom one. This follows a vote.
- With the August 2017 ranking, the field ranking of authors requires them to have 5 papers announced through NEP in that field. Only those whose first paper is 10 years or less old can also be ranked if 25% of there papers in that field.
Comments to Christian Zimmermann