A longitudinal analysis of alternative document models

Purpose – Alternative document models (ADMs) were created with the purpose of reducing the extent to which anomalies occur in counts of web links at the page level, and have been used extensively within webometrics as an alternative to using the web page as the basic unit of analysis. This paper seels tp carry out a longitudinal study of ADMs in an attempt to ascertain which model gives the most consistent results when applied to the UK, Australia and New Zealand academic web spaces over the last six years. Design/methodology/approach – Information science software (SocSciBot Tools, socscibot.wlv.ac.uk) was used to process hyperlink structure text files for UK, Australian and New Zealand universities and produced standard Page, Directory, Domain and Site ADMs using both inlinks and outlinks. Spearman bivariate correlation analysis was then undertaken to determine the level of correlation between these eight ADMs and a measure of site size for each university. Findings – The findings show that the Domain ADM gives the most consistent results. However, the Directory ADM also gives more reliable results than are evident when using the standard Page model. Aggregating at the site (or university) level appears to provide less reliable results than using the page as the standard unit of measure, and this finding holds true over all three academic webs and for each time period examined over the last six years. Research limitations/implications – The use of Spearman's correlation coefficient is considered to be unreliable when used with very small sample sizes and, with only eight universities, the New Zealand academic web space may not be sufficiently large to give truly accurate statistical results. Originality/value – While previous specific studies have shown that more accurate results can be obtained through the use of the Domain or Directory ADM, the paper has shown that these results are consistent over time and across different countries' academic web spaces.