Collaborative Information Retrieval - Collaborative Filtering systems - Recommender systems - Information Filtering • Why do we need CIR? - IR system augmentation - Filtering • Focusing on the user - People-centric view of data - Linking users by interests Recommender Systems • Broader term than CF, may not be explicitly collaborating • We get recommendations every day • Types of recommendations - Implicit - Explicit • Properties of recommendations - Identity - Experts • Use of recommendations - Aggregation from data - Leveraging naturally occurring factors Recommendation Issues • How do you get people to cooperate? • How good can the recommendations be? - Find things you’d never find? - Step savings, information navigation • Volume of recommendations vs. number of recommendable items? • How accurate can the recommendations be? - Initially - Overall - Over time • What about changing interests? Social Issues • • • • Who controls the sharing? Who controls the controls? “Give to get” systems Anonymity vs. Community - Community of “friends” - People as data points • Free riders • Logrolling and Over-rating Information Filtering & IR • How about filtering, without the collaboration? - Individual preferences - Implicit and Explicit • Text is analyzed - Feature extraction - Recall & precision measures • Vector space identified • Relevance Feedback - Matched with user or rating - Attributes are matched or added to queries Two sides of the same coin? • • • • Filtering is removing data, IR is finding data Dynamic datasets Profile-based - preferences Repeated use of the system, long term interests • Precision & Recall of profiles, not info? • Different needs & motivations • Less interactive than (Web) IR? Community Centered CF • • • • • What is a community? Helping people find new information Mapping community (prefs?) Rating Web pages Recommended Web pages - Measuring recommendation quantity? - Measuring recommendation use • Constant status Community CF • “Personal relationships are not necessary” • What does this miss? • If you knew about the user, would that help with the cold start problem? • Advisors & Trust • Ratings - Population wide - Advisors - Weighted sum • How would an organization use this? Contexts for Implicit Ratings - • • • • Who When What How (discovery) Web Browsing RSS Reading Blog posting Newsgroup- listserv use Social Affordance & Implicit • How can you not use ratings? • Read wear, clicks, dwell time, chatter • Not all resources are as identifiable - Granular- Web pages - Items - commercial products • Web is a shared informaiton space without much sharing • How do incent people to contribute? - Social norms - Rewards Contexts for Explicit Ratings • • • • • Movies Books (Junk) mail eBay transactions Other content PHOAKS • • • • • • Wider group of people (anyone?) Usenet link mining for Web resources Raters & Users Precision (88%) - belong in category Recall (87%) - rules classify as category What counts as a recommendation? - More than one mention? - Positive & negative? • Fair and balanced for a Community • How do you rank resources? - Weights - Topics Fab • • • • Beyond “black box” content Combining recommendations & content Tastes in the past & future likes Identifies “emerging interests” - Group awareness - Communication (feedback) • Profiles of content analysis compared - Users’ own profile can recommend - Relation between users can recommend • • • • User profile = multiple interests Content profile = static interest Both may change Items are continually presented to users Future Issues in Collab IR • It may be more interesting to find a like mind than a resource recommendation - Social Networking - Ad hoc group discussions • Allowing users control over their profile of interests - Over time - Privacy - Difficult to capture interests • Working with diverse content or user interests • Visualization of recommendations & areas Collaboration • How important is it to be able to collaborate? - Add to your own intelligence - Know about other things you don’t know about • What are the best scenarios for collaboration for Information Retrieval? - Privacy - Commerce - Consistency Is Filtering a Necessary Evil? • What are the Costs of Content Filtering? • Do you want filtering? - What kind of filters? - Who should control them? • What is the importance of accuracy for filtering? - Metadata - Usage and appropriate content (not just for childern) • Sharing filtering? Bonus Work • Up to 4 points on your final course average - Size of the project - Quality of project work • Individual work • Bibliography building & highlight reviews - Collaborative Filtering since 1998 - Information Seeking in Financial Environments - IR & Agents since 1999 • IR resources organization & taxonomy