25 ARL STATISTICS INTERACTIVE EDITION ON THE WORLD WIDE WEB The ARL Statistics are available through an interactive edition on the Web, supplementing previously available data from 1992‐93. Maintained and supported by the Geospatial and Statistical Data Center at the University of Virginia, this site offers researchers access to ARL Statistics with documentation.1 The site offers maps and graphics depicting current library trends. For the particularly adventurous, the site links to an interactive graphics and statistics page, allowing users to manipulate their data queries. One may chose univariate, bivariate, or multivariate statistics in addition to a vast array of selections with which to customize a query. The interactive pages also include options for regional aggregates, customized samples of observations, simple rank order tabulations of data, and the ability to create ratios of any two variables. The site also includes membership index data (volumes held, volumes added gross, current serials, total library expenditures, and total staff), as published in the Chronicle of Higher Education each spring, which can be displayed as numbers or graphs. A link provides an explanation of how the ARL membership index is used in assessing new numbers and the table of formulas for calculating the index since 1986 is also included. These and other capabilities are located at: http://fisher.lib.virginia.edu/arl/ The ARL Statistics datafiles since 1908 can be retrieved in spreadsheet format from the ARL FTP site: ftp://www.arl.org/stat/machine/ The latest ARL membership index data can be found at: http://www.arl.org/stats/factor.html The ARL Statistics and Measurement Program Web site is located at: http://www.arl.org/stats/ 1 For more information on the ARL Statistics Interactive Edition, see Martha Kyrillidou, “To Describe and Measure the Performance of North American Research Libraries,” IFLA Journal 27 (2001): 257‐63.