This document contains a detailed description of how we calculated the statistics reported on journalprices.com. The database may be updated at any time with revisions or corrections. Please contact the website owner with any questions.
Our database provides the Title, ISSN (International Standard Serial Number), Publisher, Subject(s), Price Per Article, Price Per Citation, Composite Price Index, the Year First Published, the Profit Status, Relative Value Index, and a Value category for approximately 7000 academic journals. We use the data available in the Ulrich's International Periodical Directory and the ISI Journal Citation Reports database to calculate these value statistics. In this document, "Ulrich" refers to the former and "JCI" to the latter. The calculation and/or origin of these fields for each journal in the database is described below under "Fields". All journals in the JCR database are potentially including in this database. Journals in the Ulrich directory are potentially included if they are designated to be in English, actively publishing, refereed, and indexed by either the Science Citation Index or the Social Science Citation Index. Any journal without an ISSN listed in either database is excluded. Other ways in which a journal can be excluded from this database are noted under "Calculation of Price" below. Occasionally journals change names and/or ISSN numbers. For such journals, citation counts may be underestimated. We try to make corrections for such changes if they are called to our attention, but we will not have caught every instance.
Title: The journal title is retrieved from the Ulrich directory.
ISSN: The International Standard Serial Number is retrieved from both the Ulrich directory and the JCR database.
Publisher: The journal publisher is retrieved from the JPI database.
Subject: The subject of the journal is one or more of the following list: Agriculture, Biology, Chemistry, Computer Science, Economics, Education, Engineering, Geology, History, Humanities, Law, Mathematics, Medicine, Physics, Psychology, Social Science, and Miscellaneous (Nocat). This categorization represents a blurring of the categorization provided by the JPI database with the intent of making it easy to search for journals in a particular field. Additionally, some journals labeled Nocat in the JPI database were re-categorized by hand when it was clear where they belonged.
Year First Published: This is the year in which the journal was first published. It is retrieved from the Ulrich directory. If Ulrich does not provide this information for a journal, the string "STARTDATEUNKNOWN" is displayed.
Price Per Article: The number of articles published by each journal in the five years 2000-2004 (the most recent years with data available) is retrieved from the JCR database. The price per article is simply the price of this journal for a year's subscription to an academic library (see below under "Calculation of Price" for details) divided by the average number of articles published per year.
Price Per Citation: From the JCR database, we obtain a "recent citation rate", for each journal in 2003 and in 2004. This is the number of times that volumes of a journal published between 1999 and 2003 were cited in 2003 plus the number of times that volumes published between 2000 and 2004 were cited in 2004, divided by 10. The price per citation is the price of this journal for a year's subscription to an academic library (see below under "Calculation of Price" for details) divided by the recent citation rate.
Composite Price Index: The Composite Price Index (CPI) is the geometric mean of the Price Per Article and the Price Per Citation.
Profit Status: The profit status of the journal. This was determined by hand using various internet resources. Errors should be submitted to the website manager. A few have unknown status, and these default to for-profit for the purposes of calculations since only non-profits contribute to the average non-profit price (see below). They are labeled "unknown" in this category.
Relative Price Index: The relative price index (RPI) is the CPI divided by the average CPI of non-profit journals in the same subject category. Journals that have multiple subject listings are factored into the average CPI for each field it belongs to, and its RPI is its CPI divided by the average of the average CPIs for each field.
Value: The value category is a broad categorization of a journal as "high value" "low value" or intermediate. A journal with an RPI less than 1.25 is classified as "good value", more than 2.5 as "bad value" and everything else as "medium".
The price of the journal is first retrieved from the Ulrich directory. In most cases, several prices are listed for different types of customers in different locations. We use the price most closely designated for academic libraries located in the United States. Occasionally there are several subscription options for libraries that have different prices; for example, there may be a paper edition, online edition, or combined. In this situation, the lowest price option is used.
The price, if necessary, is converted to United States Dollars using the Currency Converter.
The details of deciphering the appropriate price are complex due to the non-standard format of this information in the Ulrich directory. As many cases as we know of are handled, and if there is doubt as to which price to use, the journal is omitted from this database. However, it is still possible that errors occur, and that errors in the Ulrich directory propogate to this one.
A detailed walk-through of the method used to determine the appropriate price is available here.
Changes from previous edition of journalprices.com
The previous edition of journalprices.com was posted in November 2005. This edition used prices for the year 2004 and article and citation information for the years 1998-2002. For that edition,we used a different ISI database, Journal Performance Indicators rather than Journal Citations Reports which we are currently using. There are two important differences between these databases.The JPI, which we used for the previous edition reports recent cites in a different way from the JCR. The recent citations data from the JPI data includes all citations regardless of the year in which thecitation was made to articles written in te interval 1998-2002. Recent citations as reported by the JCR include only those citations to articles published in the most recent 5 years and cited in the most recent year. The JCR based count of recent citations is therefore considerably smaller than the count of recent citations calculated by the JPI method. As a result, our costs per citation, are systematicallyhigher in this edition than in the previous edition because of the different way of calculating citations. This change, since it affects all journals in the same way, has little effect on the relative performance of journals as we measure it.
Unfortunately, while there is a JCR for Science and for Social Science, there is not one for the Humanities. Thus we are forced to exclude some humanities journals that were included in our JPI based report.