Investigating Automated Assistance and Implicit Feedback for Searching Systems Bernard J. Jansen School of Information Sciences and Technology The Pennsylvania State University 329F IST Building, University Park PA 16802 Email: jjansen@ist.psu.edu Michael D. McNeese School of Information Sciences and Technology The Pennsylvania State University 307IST Building, University Park PA 16802 Email: mmcneese@ist.psu.edu ABSTRACT Information retrieval systems offering personalized automated assistance have the potential to improve the searching process. There has been much work in this area for several years on a variety of systems. However, there has been little empirical evaluation of automated assistance to determine if it is of real benefit for searchers. We report the results of empirical evaluation investigate how searchers use implicit feedback and automated assistance during the searching process. Results from the empirical evaluation indicate that searchers typically use multiple implicit feedback actions, usually bookmark – copy. The most commonly utilized automated assistance was for query refinement, notable the use of the thesaurus. We discuss the implications for Web systems and future research. 1. Introduction There has been considerable research into automated assistance in order to address some of the issues users have when interacting with information retrieval (IR) systems (Jansen, Spink, Bateman, and Saracevic, 1998; Yee, 1991). The need for automated assistance is especially acute with Web searching systems, as research shows that users of Web search engines have difficulty successfully implementing query syntax (Jansen, Spink, Bateman, and Saracevic, 1998), and the performance of major Web search engines (i.e., number of relevance documents retrieved within the first ten) is approximately 50% (Eastman and Jansen, 2003; Jansen and Spink, 2003). Automated assistance systems usually attempt to assist the user during the search process by either executing search tactics for or offering assistance to the user in order to help locate relevant information. We define automated assistance as any expressions, actions or responses by an IR system with the aim of improving the information searching experience for the user as measured by some external metric. These external metrics are usually relevance related ones, such as precision (Korfhage, 1997). However, there has been little empirical evaluation of automated assistance. Therefore, it is not clear whether or if automated assistance is beneficial to users during the search process. Is automated assistance helpful? If so, what type of assistance? Is it helpful for certain types of searches? When in the search process do searchers desire assistance? The research results presented in this article address a portion of these issues. We examine whether automated assistance is beneficial to users during the search process. We begin with a review of literature concerning Web and IR systems offering automated assistance. We then provide a short description of the automated assistance application we developed and utilized in the user study. Next, we discuss the empirical test we conducted to evaluate the effect of automated assistance on system performance. We present the results of our experiment and the implications for Web IR system design and then discuss directions for future research. 2. Literature Review Many searchers have difficulty effectively utilizing IR systems. These issues occur across the spectrum of IR systems, including online public access catalogs (Peters, 1993) and Web systems (Jansen, Spink, and Saracevic, 2000). For Web systems, issues include lack of query syntax (e.g., AND, MUST APPEAR, etc.), improper use of query syntax, retrieving too many results, retrieving zero results (Silverstein, Henzinger, Marais, and Moricz, 1999; Yee, 1991), among many others. Although there has been considerable research and development on advanced searching features in Web search engines, users generally do not use these features (Spink, Jansen, Wolfram, and Saracevic, 2002) and have problems with them when they do (Jansen, Spink, and Saracevic, 1998). In order to assist the user with the searching issues and to better utilize advanced searching methods, there have been efforts to develop IR systems that automate various aspects of the searching process. We refer collectively to these as automated assistance systems. Meadow and fellow researchers (1982a; 1982b) present one of the first design and analysis of a system offering contextual help. Chen and Dhar (1991) developed a system for key word selection and thesaurus browsing. Using the agent paradigm, researchers have explored intelligent IR systems for Web, including Alexa (1999) and Letizia (1995) to aid in the browsing process. ResearchIndex (Lawrence, Giles, and Bollacker, 1999) utilizes an agent paradigm to recommend articles based on a user profile. From this brief literature review, it is apparent that there has been considerable work into developing automated assistance IR systems. There has been much less research into evaluating: how do searchers utilize these systems during the searching process. We conducted a user study utilizing an automated assistance application that we developed in order to investigate these questions. 3. Research Evaluation We are interested in examining how users interact with automated assistance with the aim of improving system performance during a session. A session is one episode of a searcher using an IR system during which a series of interactions occur between the searcher and system. In this research, we specifically focus on implicit feedback actions and use of automated assistance. We next provide a short description of the automated assistance techniques we employed, and the component we developed. 4. System Development We designed and developed a client-side software component to integrate a suite of automated assistance features with a range of existing Web-based IR systems. Our system development goal was that the system would rely on implicit feedback, gleaning information solely from normal user – system interactions during the search process. The automated assistance component uses these interactions to determine what assistance to provide. 4.1 System Design The system builds a model of user – system interactions using action - object pairs (a, o) (Jansen, 2003). A single action - object (a, o) pair captures an instance of a user – system interaction. An a is some user initiated interaction with the system. An o is the receiver of that action. A series of (a, o) pairs models a searcher’s chain of interactions during the session. The system can use these (a, o) pairs to determine the user’s information need and provide appropriate assistance by associating certain actions with specific types of assistance. Using (a, o) pairs has several advantages compared to other methods of gathering information from a user during a session. The query is usually the only source of information from the user during traditional IR system interaction. Other techniques (e.g., answering questions, completing profiles, judging relevance judgments) require the user to take additional actions beyond those typical of user interactions during an online search. Using (a, o) pairs, the user’s query is not the sole representation of the information need. The system gathers additional information from other user actions, such as bookmarking, printing, emailing, without requiring additional user actions. As such, the (a, o) pair methodology is ideally suited for the implicit feedback that one expects on the Web and other client – server architectures. 4.2 System Overview The system currently monitors the searcher’s interactions with the system, tracking actions of bookmark, copy, print, save, submit, and view results. Previous research has identified these actions as implicit indications of possible document relevance (Oard and Kim, 2001). There are currently three objects that the system recognizes, which are documents, passages from documents, and queries. The system monitors the user for one of the six actions, via a browser wrapper. When the system detects a valid action (i.e., (a, o) pair), it records the action and the specific object receiving the action. For example, if a searcher was viewing this_Web_Page and saved it, the system would record this as (save this_Web_Page). The system then offers appropriate search assistance to the user based on the particular action and the system’s analysis of the object. The more (a, o) pairs the system records, the more complex the model of the information need. 4.3 Automated Assistance Offered We currently focus on five user – system interaction issues and corresponding system assistance, which are: Managing Results: Searchers have trouble managing the number of results. Using the (submit query) pair and the number of results, the automated assistance application provides suggestions to improve the query in order to either increase or decrease the number of results. If the number of results is more than thirty, the application provides suggestions to restrict the query. If the number of results is less than ten, the system provides advice on ways to broaden the query. We chose thirty and ten results as the boundary conditions based on research studies showing that approximately 80% of Web searchers never view more than twenty results (Jansen, Spink, and Saracevic, 2000). However, one can adjust the result thresholds to any targeted user population. Query Refinement: In general, most Web searchers do not refine their query, even though there may be other terms that relate directly to their information need. With a (submit query) pair and a thesaurus, the system analyzes each query term and suggests synonyms of the query terms. The system uses the Microsoft Office thesaurus, but the application can utilize any online thesaurus via an application program interface (API). Query Reformulation: Some search engines, such as AltaVista (Anick, 2003) offer query reformulation based on similar queries from previous users. We incorporated this feature into our automated assistance system. With a (submit query) pair, the system accesses a database of all previous queries and locates queries within the database containing similar terms. The system displays the top three similar queries based on number of previous submissions. Relevance Feedback: Relevance feedback has been shown to be an effective search tool (Harman, 1992); however, Web searchers seldom utilize it when offered. In the studies on the use of relevance feedback on the Web (Jansen, Spink, and Saracevic, 1999), Web searchers utilized relevance feedback less than 10% of the time. In this study, we automate the process using term relevance feedback. When the (a, o) pairs of (bookmark document), (print document), (save document), or (copy passage) occur, the system implements a version of relevance feedback using terms from the document or passage object. The system provides suggested terms from the document that the user may want to implement in a follow-on query. Spelling: Searchers routinely misspell terms in queries, which will usually drastically reduce the number of results retrieved. A (submit query) pair alerts the automated assistance application to check for spelling errors. The system separates the query into terms, checking each term using an online dictionary. The system’s online dictionary is Microsoft Office Dictionary, although it can access any online dictionary via the appropriate application program interface. 4.4 System Overview The automated assistance system has five major modules, which are: The Query Terms module uses the (submit query) pairs during a session. For each (submit query) pair, the module parses each query into separate terms, removing query operators such as the MUST APPEAR, MUST NOT APPEAR and PHRASE operators. The module then accesses the Microsoft Office dictionary and thesaurus, sending each term to the process. If there are possible misspellings, the module records the suggested corrections. The Relevance Feedback module uses (bookmark document), (print document), (save document), or (copy passage) pairs. When one of these pairs occurs, the module removes all stop words from the object using a standard stop word list (Fox, 1990) and all terms from previous queries within this session. The system then randomly selects terms remaining from the results listing abstract that was displayed or from the passage of copied text, depending on the (a, o) pair. The Reformulation module uses the (submit query) pair to provide suggested queries based on submitted queries of previous users. When a (submit query) pair occurs, the modules queries a database of all previous queries that contain all the query terms, attempting to find at least three queries to present to the user. If the database contains three queries that contain all the terms, the module selects these queries, unless one is identical to the current query. If the database contains more than three, the module selects the top three based on frequency of occurrence. If the database contains less than three, the module queries the database for queries that contain at least one of the terms, beginning with the first term in the current query. The module repeats the process until it has at least three queries to present to the searcher. One can alter the number of queries the module returns. The Refinement module uses a (submit query) pair and the number of results retrieved to suggest alternate queries to either tighten or loose the retrieval function. If the system retrieves more than thirty results, the module first checks the query for the AND, MUST APPEAR, or PHRASE operators. If the module detects no operators, it reformulates the queries using the existing terms and the appropriate AND, MUST APPEAR, or PHRASE operators. If the module detects AND or MUST APPEAR operators in the query, the module refines the query with the PHRASE operator. If the module detects PHRASE operators in the query, the module does no refinement to tighten the query. If the system retrieves less than twenty results, the module performs a similar process to broaden the query by removing of AND, MUST APPEAR and PHRASE and replacement them with the OR operator. The Tracking module monitors user interactions with the browser, including all interactions with the browser tool bars, along with the object of the interaction. The Tracking module then formulates the (a o) pair, passing the pair to the appropriate module. The Assistance module receives the automated assistance from the Query Terms, Relevance Feedback, Reformulation and Refinement modules, presenting the automated assistance to the searcher via an ASP script, which the browser loads with the Web document. For the spelling assistance, each term is presented, followed by a list of possible correct spellings. The same format is followed for synonyms. Queries with spelling corrections, similar queries, relevance feedback terms, and re-structured queries are presented as clicked text (i.e., the searcher can click on these to generate a new search). Figure 1 presents a complete system diagram. Browser Interface Assistance Modules Assistance Assistance Query Terms Table 1. Demographic of Subjects Age Mean St Dev Mode 21.4 1.96 21 Gender Male Female 35 5 Experience with Search Engines <1 1-3 3 -5 >5 Year Years Years Years 0 2 12 26 Self-Reported Skill Rating 1 2 3 4 (Novice) 0 2 Google Yahoo! 38 7 Search Engine Use (Daily) Search Engine Use (Weekly) 7 23 Alta Others Vista 2 4 Mean Range = 4.6 – 5.5 Mean Range = 30.5 – 33.1 Total 40 40 5 (Expert) 8 40 51 St Dev Range = 3.6 – 4.1 St Dev Range = 27.2 – 28.6 Relevance Feedback Reformulation Refinement Actions and Objects other information. Table 1 presents the pertinent demographic information. Tracking Figure 1: Automated Assistance Modules and Information Flow with Interface 5. User Study In the following sections, we outline our empirical evaluation. 5.1 Study Design The backend IR system utilized for the empirical study was Microsoft Internet Information Service (IIS). The IIS system is running on an IBM-compatible platform using the Windows XP operating system and Microsoft Internet Explorer as the system interface. For the automated assistance system, we integrated the automated assistance application via a wrapper to the Internet Explorer browser. The subjects for the evaluation were 40 college students (35 males and 5 females) attending a major U.S. university. All were familiar with the use of Web search engines. We gave them no additional training. We did administer a preevaluation survey to collect a variety of demographic and The average age of the subjects was 21 years. Of the subjects, twenty-six reported more than five years experience using Web search engines. The subjects selfrated their searching skills. Of the forty subjects, thirty-one rated themselves as expert or near expert. None rated themselves as novice. We also asked which search engines they used frequently. The subjects could list more than one. The most frequently reported search engine was Google. There were four search engines listed once (AOL, MSN, Ask.com, Meta-crawler). Reported frequency of search engine usage per day (subjects could report a range) averaged 4.6 to 5.5 occurrences. Weekly search engine usage averaged 30.5 to 33.1 occurrences. We utilized the Text REtrieval Conference (TREC) volumes number 4 and 5 as the document collection for the evaluation. The document collection is more than 2GB in size, containing approximately 550,000 documents. Each TREC collection comes with a set of topics for which there are relevant documents in the collection. We loaded a list of topics in a spreadsheet and coded a script to select six topics at random. The topics selected, and the ones that we utilized are: Number 304: Endangered Species (Mammals) Number 311: Industrial Espionage Number 323: Literary/Journalistic Plagiarism Number 335: Adoptive Biological Parents Number343: Police Deaths Number350: Health and Computer Terminals There were 904 TREC-identified relevant documents for the six topics, which is 0.2% of the collection. analysis, we instructed the subjects to think out loud during the searching process. All forty subjects utilized the full fifteen minutes on the system for a total of 600 minutes of video for analysis. During the sessions, we used the thinking-aloud protocol (Dumas and Redish, 1993) where the subject verbalization occurs in conjunction with a task. We used these utterances to help clarify user interactions with the system recorded in the TL. During the search sessions, we also recorded extensive lab notes on subject actions, notable utterances, and other searching behaviors. After the search session, each searcher completed a subjective evaluation of the automated assistance (Chin, Diehl, and Norman, 1988). The combination of the pre-surveys, protocol analysis, TL, and user evaluations provided a robust data source to conduct our analysis. 6. Results Figure 2: Automated Assistance after Submitting a Query At the start of the evaluation, we provided each of the subjects a short statement instructing them to search on a given topic in order to prepare a report, which is in line with the definition of relevance judgments for the TREC documents. The subjects had fifteen minutes to find as many relevant documents as possible. We determined the length of the search session based on reported measures of the “typical” Web search session (Jansen and Spink, 2003). When the subjects utilized the automated assistance system, we notified them that the system contained an automatic feature to assist them while they were searching. When the system had searching advice to offer, an assistance button would appear on the browser. We showed them a screen capture of the assistance button. We instructed them that they could access the assistance by clicking the button, or they could ignore the offer of assistance with no detrimental effect on the system. The system offered assistance whenever assistance was available. Figure 2 shows the Internet Explorer browser with the automated assistance displayed. For the searching sessions, we then gave each of the subjects one of the six search topics, read the one paragraph explanation provided with the TREC collection, and then afforded the written explanation to them. We asked the subjects to search as when they normally conducting online research, taking whatever actions they usually take when locating documents of interest online. We rotated the 6 topics among the searchers. The users were video taped during the searching process and a transaction log (TL) recorded user – system interactions. In order to add further robustness to the In the following section, we present the results of the empirical evaluation, presenting results on use of implicit feedback, and use of automated assistance. During the evaluation, ten subjects did not view or implement the automated assistance. We eliminated the results of these ten users from the evaluation in order to not to skew the evaluation. We instead report data on the thirty subjects who interacted with the automated assistance feature. 6.1 Use of Implicit Feedback Given the client – server architecture of the Web, there is a natural reliance on implicit feedback (Oard and Kim, 2001) in the identification of relevant documents for evaluation purposes. In Table 3, we present the occurrences of the implicit actions that our automated assistance application uses as surrogates for the identification of relevant documents. Table 3. Use of Implicit Relevance Actions System System Relevance Without With Total Action Assistance Assistance 186 84 102 Bookmark 87 38 49 Copy % 64.4% 30.1% Print 6 10 16 5.5% Save 4 0 4 1.4% 130 159 289 100.0 % Total For each of these actions, we verified from either lab notes or video analysis whether or not these actions implied the location of a relevant document. In all cases, these actions denoted the location of relevant information. Bookmark (64%) and Copy (30%) were the most common implicit actions (94%). What may be surprising though is that not all users relied on only one implicit action. When we analyzed what specific implicit actions individual searchers utilized, ten subjects used only Bookmark, six used only Copy, one only used Print, and one only used Save. However, ten users utilized a combined of Bookmark and Copy and three used a combination of Copy and Print. What this implies is that there may be inherent characteristics of the information objects that lend themselves to specific relevance actions by users 6.2 Use of Automated Assistance In Table 4 we present the results on the use of the automated assistance. Table 4. Use of Automated Assistance Types Assistance Type Occurrences % Query Refinement Synonyms 22 29% Query Reformulation Similar Queries 13 17% Spelling Spelling 13 17% Managing Results AND PHRASE REMOVE PHRASE Total 28 16 11 37% 21% 14% The thirty users accepted the offer of automated assistance (i.e., viewed the assistance) 108 times. They implemented some form of the assistance 76 times for a 70.4% acceptance rate. We took this high acceptance rate to be an indication that the users viewed the assistance as beneficial. Of the thirty users, three viewed the assistance at least once during the session but did not implement any assistance. Twenty-seven users viewed and implemented the assistance at least once. The mean number of viewings per user was 3.6 (sd=2.4), and the mean number of implementations was 2.5 (sd=1.8). We designed the system to offer help whenever there was assistance, meaning after every query and every implicit relevance action, the assistance button would appear on the browser. There were 233 total queries submitted by the thirty users on the automated assistance system (mean=7.77, sd=3.68) and 159 implicit relevance actions. Therefore, the assistance button appeared 392 times, of which users viewed the assistance 108 times (28%). We thought this percentage low, assuming that the novelty factor alone would entice users at least to view the assistance. From analysis of comments during the session and the postsearch survey, there appears to be least two major reasons for not viewing the assistance. There is a sizeable portion of searchers who just like to attempt things on their own first and seek assistance only when needed. If they believe they are doing okay, they see no need for system assistance. The second major reason concerns interface design issues. We had attempted to make the assistance button very nonintrusive. However, it appears that there must be some intrusiveness into order to attract the attention of searchers. 7. Discussion 1 76 1% 100% From Table 4, we see that the most commonly implemented assistance was Managing Results (37%). Of these, all but one was assistance to decrease the number of results (i.e. the use of the AND and PHRASE operators). The subjects also utilized the other forms of assistance quite frequently, with Query Refinement also being commonly used assistance. The subjects did not use the Spelling feature as much as we expected, since research reports that Web searchers frequently misspell terms (Jansen, Spink, and Saracevic, 1998). However, we did furnish the searchers with the written TREC topic description for their search. Most searchers referred to this sheet for formulating some of their initial queries. Returning to our research question (How do searchers utilize these systems during the searching process?), searchers interact with automated assistance system in some interesting and occasionally unexpected ways. There are certain implicit relevance actions that searchers prefer, primarily Bookmark, which was the action of choice by twenty of the thirty users, either alone (10) or in combination with the action Copy (also 10). Copy was also a top choice of the searchers, again either alone (6) or in combination with Bookmark (10). Why searchers make these choices could lead to improvements in system support during the searching process. Are these choices solely user specific or are there some characteristics of the information objects that lead themselves to certain searcher relevance actions? Concerning the use of automated assistance, users most commonly implemented assistance to Manage Results, and overwhelmingly these selections were actions to tighten the query, thereby attempting to reduce the number of results. This would indicate that users consider result management, particularly precision, a key issue for Web searching. Searchers also used Query Refinement, specifically the use of synonyms, extensively (29% of all implementations). Given the low percentage of relevant documents in the collection (0.2%), many subjects found the searching difficult, expressing their frustration with the topic difficulty during the search. In these searching situations, term selection is extremely important, perhaps even more important than selection of query operators (Eastman and Jansen, 2003). In general though, searchers were inclined not to view assistance (72%) when it was offered. Searchers have a tendency to want to search on their own. Several searchers did not even notice the search button until well into the search session, even though the button was placed just below the search text box. However, we did attempt to make the assistance button non-intrusive. Given the cognitive load that searching requires, it appears that some intrusiveness is necessary to gain the attention of the searcher. Of the thirty searchers who viewed the assistance, twentyseven (90%) implemented the assistance. Of the 108 times that searchers viewed the assistance, they implemented it 76 times (70%). This indicates that once they did view system assistance, they deemed the assistance beneficial. Again, this may be a justification for more direct and target intrusion into the searching process. This is the technique that Google and AltaVista employ with their Did you mean spelling assistance. 8. Conclusion and Future Research The results of the research conducted so far are very promising. Results indicate that searchers interact with these systems in predictable ways, which might be utilized to improve the design of future systems. We are continuing our performance evaluation of the automated assistance system at the query and session level of analysis using the TREC identified relevant documents. We also plan to conduct a temporal analysis to see if there are patterns of interaction that would predict when a searcher desires assistance from the system. By detecting the patterns of user – system interaction, designers can tailor IR systems to provide targeted assistance at the proper temporal states when the user is willing to view or implement the assistance. With this information, IR systems may more effectively assist searchers in locating the information they desire. 9. References Anick, P. (2003). Using Terminological Feedback for Web Search Refinement - a Log-Based Study. 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