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  4. Usor Economicus – Modelling Search Interaction using Economics




Usor Economicus – Modelling Search Interaction using Economics




Speakers: Leif Azzopardi, University of Strathclyde

Series: HCID Research Seminars

Seminar Abstract:

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 Interactive Information Retrieval 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.

This talk is based on the following papers:

“The economics of interaction”, ACM SIGIR 2011, see:

“How query cost affects search behavior” with Diane Kelly & Kathy Brennan at ACM SIGIR 2013, see:

“Modeling Interaction with Economic Models of Search” which received an Honorable Mention at ACM SIGIR 2014, see:

“An analysis of Theories of search and search behaviour” with Guido Zuccon at  ACM ICTIR 2015, see:

“An analysis of the Cost and Benefit of Search Interactions” with Guido Zuccon, at ACM ICTIR 2016, see

About the speaker:

Dr. Leif Azzopardi is a Chancellor’s Fellow at the University of Strathclyde, Glasgow within Department of Computer and Information Science. Prior to this he was a Senior Lecturer at the University of Glasgow within the School of Computing Science. His latest research focuses on using Optimal Foraging Theory and Economic Theory to model the interaction between users and information retrieval systems.

Central to his research is the theoretical development of statistical language models for Information Retrieval, where his research interests include:(i) Models for the retrieval of documents, sentences, experts and other information objects,(ii) Probabilistic models of user interaction and the simulation of users for evaluation,
(iii) economic models of information interaction, specifically how cognitive load and effort affect interaction and performance with search systems,
(iv) Methods for text and data mining of large scale/big data collections,
(v) Methods which assess the impact of search technology on society in application areas such as, search engine bias and the accessibility of E-Government information.

He received his Ph.D. in Computing Science from the University of Paisley in 2006, and he received a First Class Honours Degree in Information Science from the University of Newcastle, Australia, 2001.

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When & where

1.00pm - 2.00pmFriday 24th March 2017

AG08 College Building City, University of London St John Street London EC1V 4PB United Kingdom

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City, University of London

Northampton Square

London EC1V 0HB

United Kingdom

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City, University of London is an independent member institution of the University of London. Established by Royal Charter in 1836, the University of London consists of 18 independent member institutions with outstanding global reputations and several prestigious central academic bodies and activities.