CORIA 2015

Jeudi – L. Azzopardi – Usor Economicus


To paraphrase the political economist, John Stuart Mill:

The Information Economy does not treat the whole of man’s nature as modified by the system nor the whole conduct of man in society. It is concerned with him solely as a being who desires to possess knowledge, and who is capable of judging the comparative efficacy of means for obtaining that end.

In this talk, I will describe my efforts in trying to understanding how people interact with search systems and how this has resulted in the development of several economics model of search and search behaviour. These models assume an Economic User (i.e. Usor Economicus), one who inevitably does that by which s/he may obtain the greatest amount of information and knowledge, with the smallest quantity of effort. In this talk, I will first provide an overview of the typically IIR process. Then I will introduce an economic model of search, which is derived from production theory. I will show how the model enables us to generate compelling, intuitive and crucially testable hypotheses about the search behaviour of users. They provide insights into how we can manipulate the system and the interface in order to change the behaviour of users. In a series of user experiments, I show how well the models characterise, predict and explain observed behaviours (and where they fall down). I believe the models, not only, provide a concise and compact representation of search and search behaviour, but also provides a strong theoretical basis for future research into interactive Information Retrieval. Furthermore, these economic models can be developed for all sorts of human computer interactions, and so are likely to provide many more insights into how people use systems and how we should design such systems.


Dr. Leif Azzopardi is a Senior Lecturer within the School of Computing Science at the University of Glasgow, and member of the legendary Glasgow Information Retrieval Group. His research focuses on building formal models for Information Retrieval – usually drawing upon different disciplines for inspiration, such as Quantum Mechanics, Operations Research, Microeconomics, Transportation Planning and Gamification. His research interests include:

  • Models for the retrieval of documents, sentences, experts and other information objects,
  • Probabilistic models of user interaction and the simulation of users for evaluation,
  • Microeconomic models of information interaction, specifically how cost and effort affect interaction and performance with search systems,
  • Methods which assess the impact of search technology on society in applica- tion areas such as, search engine bias and the accessibility of e-Government information, and,
  • Searching for fun (i.e. the SINS of users).

He received his Ph.D. in Computing Science from the University of Paisley, Scotland in 2006, and he received a First Class Honours Degree in Information Science from the University of Newcastle, Australia, 2001. In 2010, he received a Post- Graduate Certificate in Academic Practice and has been lecturing at the University of Glasgow ever since.

He has published over 100 publications and given numerous invited talks on Retrievability and Formal Models of Information Seeking and Search throughout the world and lectures at the Information Foraging Summer School (2011, 2012 and 2013). In 2007, he created the Symposium on Future Directions in Information Access (FDIA), which is decimated to promoting PhD students, and has been ran from 2007-2013 at the European Summer School Summer in Information Retrieval (ESSIR). In 2014, he released a free online book called, How to Tango with Django which is a noob’s guide to web development in Python’s Django (available online and free at:, which has seen over 250,000 visitors). He goes by the hacker name: leifos on skype, twitter and github, and his website is:

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