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Finding and Re-Finding Through Personalization. Jaime Teevan MIT, CSAIL. David Karger (advisor), Mark Ackerman, Sue Dumais, Rob Miller (committee), Eytan Adar, Christine Alvarado, Eric Horvitz, Rosie Jones, and Michael Potts. Thesis Overview. Supporting Finding How people find
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Finding and Re-Finding Through Personalization Jaime Teevan MIT, CSAIL David Karger (advisor), Mark Ackerman, Sue Dumais, Rob Miller (committee), Eytan Adar, Christine Alvarado, Eric Horvitz, Rosie Jones, and Michael Potts
Thesis Overview • Supporting Finding • How people find • Individual differences affect finding • Personalized finding tool • Supporting Re-Finding • How people re-find • Finding and re-finding conflict • Personalized finding and re-finding tool
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Thesis Overview • Supporting Finding • How people find • How individuals find • Personalized finding tool • Supporting Re-Finding • How people re-find • Finding and re-finding conflict • Personalized finding and re-finding tool
Supporting Re-Finding • How people re-find • People repeat searches • Look for old and new • Finding and re-finding conflict • Result changes cause problems • Personalized finding and re-finding tool • Identify what is memorable • Merge in new information
Supporting Re-Finding • How people find • People repeat searches • Look for old and new • Finding and re-finding conflict • Result changes cause problems • Personalized finding and re-finding tool • Identify what is memorable • Merge in new information Query log analysis Memorability study Re:Search Engine
Related Work • How people re-find • Know a lot of meta-information [Dumais] • Follow known paths [Capra] • Changes cause problems re-finding • Dynamic menus [Shneiderman] • Dynamic search result lists [White] • Relevance relative to expectation [Joachims]
Query Log Analysis • Previous log analysis studies • People re-visit Web pages [Greenberg] • Query logs: Sessions [Jones] • Yahoo! log analysis • 114 people over the course of a year • 13,060 queries and their clicks • Can we identify re-finding behavior? • What happens when results change?
Re-Finding Common Unique click Repeat click 40% 86% of queries of queries Repeat query 33% 26% of queries of queries 87% 38% of repeat queries of repeat queries
Change Reduces Re-Finding • Results change rank • Change reduces probability of repeat click • No rank change: 88% chance • Rank change: 53% chance • Why? • Gone? • Not seen? • New results are better?
Change Slows Re-Finding • Look at time to click as proxy for Ease • Rank change slower repeat click • Compared with initial search to click • No rank change: Re-click is faster • Rank change: Re-click is slower • Changes interfere with re-finding ?
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Abracadabra! Case 1Case 2Case 3Case 4Case 5Case 6
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Memorability Study • Participants issued self-selected query • After an hour, asked to fill out a survey • 129 people remembered something
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Re:Search Engine Architecture Search engine result list query 1 query 2 … query n result list 1 result list 2 … result list n Index of past queries score 1 score 2 … score n Result cache Merge query result list User interaction cache Web browser User client
Components of Re:Search Engine query 1 query 2 … query n query Index of past queries score 1 score 2 … score n • Index of Past Queries • Result Cache • User Interaction Cache • Merge Algorithm result list 1 result list 2 … result list n query 1 query 2 … query n Result cache User interaction cache result list result list 1 result list 2 … result list n Merge result list
Index of Past Queries query 1 query 2 … query n query Index of past queries score 1 score 2 … score n • Studied how queries differ • Log analysis • Survey of how people remember queries • Unimportant: case, stop words, word order • Likelihood of re-finding deceases with time • Get the user to tell us if they are re-finding • Encourage recognition, not recall
Merge Algorithm result list result list 1 result list 2 … result list n Merge result list • Benefit of New Information score • How likely new result is to be useful… • …In a particular rank • Memorabilityscore • How likely old result is to be remembered… • …In a particular rank • Chose list maximizes memorability and benefit of new information
Benefit of New Information • Ideal: Use search engine score • Approximation: Use rank • Results that are ranked higher are more likely to be seen • Greatest benefit given to highly ranked results being ranked highly
Memorability Score • How memorable is a result? • How likely is it to be remembered at a particular rank?
Choose Best Possible List • Consider every combination • Include at least three old and three new • Min-cost network flow problem New b1 … b2 7 10 t b10 s 10 … m1 … 7 m2 … Slots m10 Old
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Evaluation • Does merged list look unchanged? • List recognition study • Does merging make re-finding easier? • List interaction study • Is search experience improved overall? • Longitudinal study
List Interaction Study • 42 participants • Two sessions a day apart • 12 tasks each session • Tasks based on queries • Queries selected based on log analysis • Session 1 • Session 2 • Re-finding • New-finding (“stomach flu”) (“Symptoms of stomach flu?”) (“Symptoms of stomach flu?”) (“What to expect at the ER?”)
Old New Experimental Conditions • Six re-finding tasks • Original result list • Dumb merging • Intelligent merging • Six new-finding tasks • New result list • Dumb merging • Intelligent merging New 1 New 2 New 3 New 4 New 5 New 6 Old 5 New 1 Old 1 Old 7 New 2 New 3 New 4 Old 4 New 5 New 6
Old New Experimental Conditions • Six re-finding tasks • Original result list • Dumb merging • Intelligent merging • Six new-finding tasks • New result list • Dumb merging • Intelligent merging Old 1 Old 2 Old 4 New 1 New 2 New 3 New 4 New 5 New 6 Old 10 Old 1 Old 2 Old 4 Old 10
Measures • Performance • Correct • Time • Subjective • Task difficulty • Result quality
Experimental Conditions • Six re-finding tasks • Original result list • Dumb merging • Intelligent merging • Six new-finding tasks • New result list • Dumb merging • Intelligent merging Faster, fewer clicks, more correct answers, and easier! Similar to Session 1
Results: Re-Finding 99% 88% 38.7 70.9 45.6
Results: Re-Finding 1.79 1.53
Results: Re-Finding Similarity 76% 60% 76% • Intelligent merging better than Dumb • Almost as good as the Original list
Results: New-Finding 153.8 120.5
Results: New-Finding 3.38 2.94
Results: New-Finding Similarity 38% 50% 61% • Knowledge re-use can help • No difference between New and Intelligent
Results: Summary • Re-finding • Intelligent merging better than Dumb • Almost as good as the Original list • New-finding • Knowledge re-use can help • No difference between New and Intelligent • Intelligent merging best of both worlds
Conclusion • How people re-find • People repeat searches • Look for old and new • Finding and re-finding conflict • Result changes cause problems • Personalized finding and re-finding tool • Identify what is memorable • Merge in new information