A BSTRAC T This paper reports a study on the relationships between work tasks and users' performance when they interact with information systems, that is, interaction performance. An experiment with 24 participants was conducted to explore the issue . The partic ipants were asked to search for useful info rmation to support the completion of six simulated work task situat ions from operat ional information systems. Users ' interac tion pe rformance is measured based on users' search effectiveness and efficiency. The results indicate: 1) Work tasks and time sufficiency for the searc h dramatically affect users ' interaction performance. 2) Information sufficiency affects users ' percept ion of their interaction per formance .3) The two facet of work tasks, i.e. product and objective work task complexity, sign ifican tly and interactively affect users' interaction perfo rmance to different degrees. 4) In contrast to product, objective work task complexity is more influential on users ' interactio n performance. 5) In addition , the study identifies some indicators of work task characteristics, for example, the number of items users select to support their wor k tasks and the search time they spend in loca ting useful information for a work task. The results shed light on the role of work task in information search and retrieval. The findings help improve interactive information systems design and personalization of information retr ieval.Ke ywords Wo rk tasks , interaction performance, information search and retr ieval.
INTRO DUCTIONTask is one of the factors that mot ivate users to interact with information system. Some researchers have explored how work tasks influence d users ' information-seeking or Land ry, 2006). These studies found that informationseeking or search activities were important for work task completion. However, few stud ies directly examine the effect of work tasks on users' interaction perfo rmance . In fact, when users interact with information systems , mostly, their purpose is to locale useful information that could support them to complete their work tasks. Their performance is critical since successful search activities can directly influence their work task completion. Moreover, the ultimate goal of information syste ms is to help users locate valuable information and help them complete their work task at hand. The refore , it is important to design useful and usable information systems to facilitate users to complete their work tasks . For this purpose , it is imperative to understand how work tasks affect users ' interaction performance .Several types of tas ks have been investigated in information science. Among these tasks, work task and search task are mostl y concerned. According to Ingwersen and Jarvelin (2005), the notion of work tasks is central to informatio n seeking and retrieval. It refers to bo th job-related and dailylife work tasks. Search tasks are carried out by information seekers as a means to gather informa tion for the purpose to fulfill work tasks at hand. For the ...