A theory of the task-based information retrieval process: a summary and generalisation of a longitudinal study Pertti Vakkari Article information:To cite this document: Pertti Vakkari, (2001),"A theory of the task-based information retrieval process: a summary and generalisation of a longitudinal study"Access to this document was granted through an Emerald subscription provided by emerald-srm:463575 [] For AuthorsIf you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation.The aim of this article is threefold: (1) to give a summary of empirical results reported earlier on relations between students' problem stages in the course of writing their research proposals for a master's thesis and the information sought, choice of search terms and tactics and relevance assessments of the information found for that task; (2) to show how the findings of the study refine Kuhlthau's model of the information search process in the field of information retrieval (IR); and (3) to construe a tentative theory of a task-based IR process based on the supported hypotheses. The results of the empirical studies show that there is a close connection between the students' problem stages (mental model) in the task performance and the information sought, the search tactics used and the assessment of the relevance and utility of the information found. The corroborated hypotheses expand the ideas in Kuhlthau's model in the domain of IR. A theory of task-based information searching based on the empirical findings of the study is presented.

IntroductionThe rationale for using information systems is to find information that helps us in our daily activities, be they tasks or interests. Systems are expected to support us in searching for and identifying useful information. Although the activities and tasks performed by humans generate information needs and searching, they have attracted little attention in studies of information searching. Such studies have concentrated on search tasks rather than the activities that trigger them. It is obvious that our understanding of information searching is only partial, if we are not able to connect aspects of searching to the related task. The expected contribution of information to the task is reflected in relevance assessments of the information items found, and in the search tactics and use of the system in general. Taking the task into account seems to be a necessary condition for understanding and explaining information searching, and, by extension, for effective systems design. Scope and ApproachIn this chapter, I shall review studies on the relationship between task performance and information searching by end-users. I focus mainly on 41 3 414 Annual Review of information Science and Technology information searching in electronic environments, especially in information retrieval (IR) systems. The process of information searching is cyclical, but it can be broken down into the following components:The kind of information that is needed and searched forThe query formulation process, including the choice of search terms and operators Search tacticsThe use of search support tools Relevance and utility judgments regarding the information found Several approaches to characterizing tasks in the literature are in use. In the studies I have found on information searching, tasks have been either characterized as a process consisting of several stages, or this aspect has been left open. In the latter case, the task has been treated as a given and left without characterization; only its context being described. A typical example is observing university students searching for information for study purposes without explicating those purposes. In these studies, the point of departure is searching, not the work task that produces it.Only a limited number of studies relate tasks to searching. Because of this, I take into account studies based on natural search goals, insofar as they further our understanding of task-based searching. I also review a few studies based on assigned search goals. In general, the models and findings are scattered and difficult to integrate into the framework of task-based searching.Ideally, a study should connect the task with the search process in order to analyze their interaction (Belkin, 1990). This sort of study typically requires a longitudinal research design. Due to the rarity of such process analyses, studies that analyze the relation between tasks and searching synchronously are also included. I focus principally on the literature published after 1990 simply because the number of empir...

The objective of this study is to analyse how changes in relevance criteria are related to changes in problem stages during the task performance process. Relevance is understood as a task-and processoriented user construct. The assessment of relevance is based on both retrieved bibliographical information and the documents acquired and read on the basis of this information. The participants of the study were eleven students who attended a course for one term for preparing a research proposal for the master's thesis. The students were asked to make an IR search at the beginning, middle and end of the course. Data for describing their understanding of the work task, search goals and tactics as well as relevance assessments were collected during the search sessions. Pre-and postsearch interviews were conducted during each session. The students were asked to think aloud during the search session. The transaction logs were captured and the thinking aloud was recorded. Research and search diaries were also collected. The findings support to a certain extent the overall hypotheses that a person's problem stage during task performance is related to his or her use of relevance criteria in assessing retrieved references and documents. There is a connection between an individual's changing understanding of his or her task and how the relevance of references and full texts is judged. The more structured the task in the process, the more able the person is to distinguish between relevant and other sources. The relevance criteria of documents changed more than the criteria of references during the process. Moreover, it seems that understanding of topicality varies depending on the phase of the process.

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The paper surveys empirical studies on the relations between information searching and learning, and presents some reflections about learning in a search process based on the findings. First, the meaning of the concepts 'learning' and 'searching' is briefly defined. Learning is conceptualized as changes in one's knowledge structures. Then it is described more in detail how learning occurs in the search process. The point of departure is to focus on tasks that require the restructuring of knowledge structures and to analyse how gradual stabilization of those structures is related to accessing and interacting with information sources. After that, empirical studies on searching and learning are categorized by identifying independent and dependent variables in those studies. In conclusion, some general remarks on the topic are presented.

Evaluation is central in research and development of information retrieval (IR). In addition to designing and implementing new retrieval mechanisms, one must also show through rigorous evaluation that they are effective. A major focus in IR is IR mechanisms' capability of ranking relevant documents optimally for the users, given a query. Searching for information in practice involves searchers, however, and is highly interactive. When human searchers have been incorporated in evaluation studies, the results have often suggested that better ranking does not necessarily lead to better search task, or work task, performance. Therefore, it is not clear which system or interface features should be developed to improve the effectiveness of human task performance. In the present article, we focus on the evaluation of task-based information interaction (TBII). We give special emphasis to learning tasks to discuss TBII in more concrete terms. Information interaction is here understood as behavioral and cognitive activities related to task planning, searching information items, selecting between them, working with them, and synthesizing and reporting. These five generic activities contribute to task performance and outcome and can be supported by information systems. In an attempt toward task-based evaluation, we introduce program theory as the evaluation framework. Such evaluation can investigate whether a program consisting of TBII activities and tools works and how it works and, further, provides a causal description of program (in)effectiveness. Our goal in the present article is to structure TBII on the basis of the five generic activities and consider the evaluation of each activity using the program theory framework. Finally, we combine these activity-based program theories in an overall evaluation framework for TBII. Such an evaluation is complex due to the large number of factors affecting information interaction. Instead of presenting tested program theories, we illustrate how the evaluation of TBII should be accomplished using the program theory framework in the evaluation of systems and behaviors, and their interactions, comprehensively in context.

End-users base the relevance judgements of the searched documents on the expected contribution to their task of the information contained in the documents. There is a shortage of studies analyzing the relationships between the experienced contribution, relevance assessments and type of information initially sought. This study categorizes the types of information in documents being used in writing a research proposal for a master's thesis by eleven students throughout the various stages of the proposal writing process. The role of the specificity of the searched information in influencing its contribution is analyzed. The results demonstrate that different types of information are sought at different stages of the writing process and thus the contribution of the information also differs at the different stages. The categories of the contributing information can be understood as aspects of topicality. KeywordsField/empirical studies of the information seeking process, embedding search within larger tasks, cognitive models and IR, situational relevance