COUNTER published the Code of Practice for Usage Factors (UF) in March 2014. It is a useful tool openly available for use by any publisher who wishes to implement it.
The Usage Factors (UF) for Journals is the Median Value in a set of ordered full-text article usage data (i.e. the number of successful full text article requests) for a specified Usage Period of articles published in a journal during a specified Publication Period.
The availability credible COUNTER-compliant online usage statistics, made JUF possible as a usage-based measure of journal performance. Like Impact Factor, it is scale independent. In other words, it can be used to compare journals irrespective of their size.
Authors, especially those in practitioner-oriented fields, where citation-based measures understate the impact of journals, as well as those in areas outside the core STM fields of pure research, where coverage of journals by citation-based measures is weak.
Publishers, especially those with large numbers of journals outside of the core STM research areas, where there is no reliable, universal measure of journal impact, because citation-based measures are either inadequate or non-existent for these fields.
Librarians, when deciding on new journal acquisitions, have no reliable, global measures of journal impact for fields outside the core STM research fields. They would use usage-based measures to help them prioritise journals to be added to their collections.
Research Funding Agencies, who are seeking a wider range of credible, consistent quantitative measures of the value and impact of the outputs of the research that they fund.
Extensive testing of usage data for 224 journals in 27 different subject fields was collected from 7 publishers and 12 and 24-month Journal Usage Factors calculated for them using the following formulae, with the years 2009 and 2010 as examples:
12 Month 2010 Usage Factor for Journals: all items:
The median number of successful requests for countable items during 2010 for items published in the journal during 2010
24 Month 2009/2010 Usage Factor for Journals: all items
The median number of successful requests for countable items during 2009/2010 for items published during 2009/2010.
Some useful observations were made about the UF for Journals calculated in the development project:
a. Within each subject area the spread of UFs for both 12 and 24 month periods appeared to be sufficiently large to allow journals to be differentiated.
b. In the great majority of cases the 12 and 24 month UF rankings place the top 5 journal in each subject area in pretty well the same order. The exceptions to this are some fields in the social sciences, where the rankings change more dramatically. The time decay of usage in social sciences is slower than in the physical and life sciences, so a smaller proportion of lifetime usage is captured in the first 12 months of an article’s life.
c. The median value UF-based journal rankings appear to be reasonably stable from year to year.
The final Usage Factor for Journals was determined to be:
The median number of successful requests for countable items during a 24-month usage period for items published during the same 24-month publication period.
Implementing the Usage Factor for Journals
The Usage Factor for Journals must be calculated on the basis of COUNTER-compliant usage data, consistent with the data processing rules specified in the COUNTER Code of Practice for Articles.
Points of note
Usage Factors should be calculated using the median rather than the arithmetic mean
A range of Usage Factors should ideally be published for each journal: a comprehensive UF (all items, all countable versions) plus supplementary factors for selected items, particularly articles only
Usage Factors should be published as integers with no decimal places
Usage Factors should be published with appropriate confidence levels
The Usage Factor should be calculated initially on the basis of a usage time window of 24 months.
The Usage Factor is not directly comparable across subject groups and should therefore be published and interpreted only within appropriate subject groupings.
The Usage Factor should be calculated using a publication window of 2 years
Research articles (full articles and short communications). Only usage of the following 5 Article Versions: o Accepted Manuscript (AM) o Proof (P) o Version of Record (VoR) o Corrected Version of Record (CVoR) o Enhanced Version of Record (EVoR)
Editorial board lists
Permission details: Author’s Original (AO), Submitted Manuscript, Under Review (SMUR)
Articles covered in UFJ1b are: short communications, full research articles and review articles
All journals included in the report must be allocated a Subject Category consistent with the Subject Classification in Appendix D
The Usage Factors for any given Usage Period must be published within 3 calendar months of the end of that Usage Period. Thus, the Usage Factor for the Usage Period 2009/2010 must be published before 31 March 2011.
Usage Factors should be ranked within subject groupings in descending numerical order.
Usage Factor for Journals – the calculation
Two categories of Usage Factor may be calculated
The 24-month Usage Factor all content: The median number of successful requests during 24 months for example 2014/2015 to content published in the journal in 2015/2016
The 24-month Usage Factor full-text articles only: The median number of successful requests during 24 months for example 2014/2015 to full-text articles published in the journal in 2014/2015