A Semester of Searches: Fall 2012

The Fall 2012 semester is officially over at the University of Michigan. I thought it would be interesting to compile some statistics on site search and how this year compared to past years.

We built a log file parser a few years ago that crawls the web server logs every night and extracts some general information about the number of searches conducted on the library site. We include searches entered into any of the three tabs in the search box at the upper left of all library web pages as well as searches entered in Mirlyn, the library catalog. We anonymize the data, attempt to remove page refreshes and duplicate searches, and store the data away for future use.

The fall semester at the University of Michigan is 112 days long (111 in 2010). For year-over-year data gathering, I defined the semester as starting with registration and ending on the last day of exams. In 2012, that means August 31 to December 20, inclusive. During the fall semester, library website visitors conducted a total of 1,201,103 searches.

Search Category Searches 2010 Searches 2011 Searches 2012
MLibrary 440,220 431,592 431,500
Articles * 110,702 245,898 326,457
Catalog ** 15,154 492,157 443,146
Total 566,076 1,164,360 1,201,103

* Includes both searches from the ArticlesPlus tab in the search box and searches launched from the ArticlesPlus interface.
** Includes both searches from the Catalog tab in the search box and searches launched from the library catalog, except for 2010 where it only includes searches from the Catalog tab on the site search -- not searches originating in Mirlyn itself.

Search Patterns

The pattern of search volume overall is very regular and predictable year over year, as shown in this chart. For the previous two years, the peak day was on day 88; this year, it was (by slim margin of 175 searches), the following day, day 89 (November 27, 2012). Still the peaks and valleys track from year to year with clear regularity.

Searches by Category

One Search

Searches in the library's default MLibrary tab are remarkably constant across the past three years. The MLibrary tab is our "one search" tab, bringing back results from several categories: databases, journals, items from the catalog, research guides, web pages, collections, subject specialists, and the staff directory.

Article Discovery

The ArticlesPlus tab in our site search, and the ArticlesPlus article discovery service that underlies it, has shown significantly increased usage over the past few years. For most of 2010, from January through late September, the article search tool was driven by Ex Libris' Metalib product. In September 2010, the library launched a Summon-powered interface (see ArticlesPlus: Article Discovery on MLibrary Site for more information on ArticlesPlus). Usage increased immediately, and has been growing every since.

The growth of use of the Summon-driven article search compared to Metalib is striking from the day it launched (day 27, or September 22, 2010). Daily searches in fall 2012 exceeded the equivalent day in fall 2011 each and every day.


Where MLibrary searches were essentially the same for the past two years, and ArticlesPlus searches increased significantly, Catalog searches decreased by about 10%. The relative highs and lows tracked fairly well, though not as closely in step as the other two categories. (The blue line for 2010 shows only Catalog searches from the Catalog tab in the search box, unlike 2011 and 2012, when searches from within the catalog were included.)

Looking Forward

Looking ahead to Winter 2013, I'll predict that the peak search day will be day 99 or 100.