How much is much?

Tord HøivikOslo University College

Hits and readers

• We are a trusted and independent source, • both in cyberspace • and through our vast printed collections, • with more than 67 million hits on our website in

the past 12 months • and 500,000 readers passing through our doors

every year.  

Dame Lynne Brindley, Director, British Library, 2008.   

Visits and visitors in real life (IRL)

Make statistics meaningful  • half a million visits per year• forty thousand visits per month• ten thousand visits per week • fifteen hundred visits per day 

 • visits = visits to the reading room• the library has about 1300 reading desks• and about five hundred additional seats• such as terminals, microform readers, carrels

Visits and visitors IRL (cont.)

• open to everyone who has a genuine need to use its collections

• most suited to those wishing to use specialised material that is not always available in public or academic libraries. ...  

• criticism for admitting undergraduate students (who have access to their own university libraries) to the reading rooms

• have always admitted undergraduates as long as they have a legitimate personal, work-related or academic research purpose

• 0,8 visits per hundred inhabitants of the UK• 4 visits per hundred residents in Greater London • x visits per academic in Greater London 

Visits and visitors in virtual life (IVL)

• seventy million hits per year• two hundred thousand hits per day 

 Hits and visits  • a hit = a page view = a request made to a BL web server for

a page• a visit = a sequence of requests from a uniquely identified

client (computer)  

Hits and visits

• 6,5 hits (page views) per visit in Royal Danish Library (2005)

• 8,5 hits per visits in 2006• 7-8 hits per visit ?

 • 25-30 thousand virtual visits per day  • 175-210 thousand virtual visits per week• 750-900 thousand virtual visits per month• 9-10 million virtual visits a year

  

How long does a visit last?

•  typical web users spend about one minute per page

• a virtual British Library visit probably lasts seven or eight minutes - on the average 

• a physical British Library visit probably lasts several hours - on the average 

  

The distribution of visits

• Traffic may be concentrated, with a few visitors making many visits each

• Traffic may be dispersed, with lots of visitors making few visits each

 • In the first case the number of unique visitors in a year (say)

will be low relative to the total number of hits and visits• In the second case the number of unique visitors will be high

 • Usually we find a combination of heavy and light users• The visits follow a "power-law" or a "long-tail" or a "J-

shaped" distribution   

Unique visitors

We can sum up the BL data in 06/07 as follows:

• five million unique users per year• nine to ten million visits per  year (est.)

 On the average • about two visits per user • seven to eight pages per visit • seven to eight minutes per visit

 The average virtual user spends about fifteen minutes on the BL web site during a year - and reads about fifteen pages 

The Pareto hypothesis• We lack data on light versus heavy users of the web site.• The Pareto principle states that 20 percent of the units represent 80 percent of the activity.• The Pareto principle often describes long-tail distributions rather well. 

 This provides the hypothesis: 

• One million heavy users visit the BL web site frequently - and download  about fifty million pages a year• Four million light users visit the BL web site occasionally - and download about thirteen million pages

  

  f we assume that the Pareto principle holds,

• five million unique users per year• nine to ten million visits per  year (est.)

 On the average • about two visits per user • seven to eight pages per visit • seven to eight minutes per visit

 The average virtual user spends about fifteen minutes on the BL web site during a year - and reads about fifteen pages 

Web traffic in the North

Page views (hits)  United Kingdom: 1,1 per inhabitant (07)Finland: 1,3  (average 04-07)Norway: 1,7 (average 06-07)Denmark: 6,5 (06)

Visits

Sweden: 0,2 per inhabitant (06)Denmark: 0,7 (average 06-07)

Web traffic in Norway 1

More than 100 million hits per week

• Norway's largest newspaper (VG)• Norway's biggest site for classified advertisments (Finn)

 Between 10 and 100 million hits per week • one web service (MSN)• one financial magazine• three search-oriented sites• four news-oriented sites

 

Web traffic in Norway 2

Between 1 and 10 million hits per week

• Thirty-nine sites Between 100 thousand and 1 million hits per week • Thirty-seven sites• National Library: 160 thousand hits  

 

How much is much?

1.In the past, libraries measured their collections2.At present, libraries measure their activities3.In the future, libraries must measure their impact.

  

Numbers charged with meaning

1. At present, indicators of physical activities are much more developed than indicators of virtual activities

2. But even our physical indicators need much more real-life, in-library testing.

3. Web metrics face the same challenge: they must be tried out and evaluated in real, practical situations. 

4. In order to flourish, indicators require decisions and decision-makers that utilize indicators.

5. This will only happen when numbers are charged with meaning. 

  

Resources

  Paper at IFLA web site:  • http://www.ifla.org/IV/ifla74/papers/160-Hoivik-en.pdf

 Other • Poll, Roswitha and Peter te Boekhorst. Measuring quality.

Performance measurement in libraries. München: Saur, 2007. 2. edition.

• Web analytics. Wikipedia. URL= http://en.wikipedia.org/wiki/Web_analytics