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Differences Between Observed and Latent Confidence in Rank Ordering. Brent J. Miller Mark Steyvers University of California, Irvine. Getting Expert Information. Getting Expert Information. Delphi Method. Iterative Collaboration. Independent Rank-Ordering Tasks.
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Differences Between Observed and Latent Confidence in Rank Ordering Brent J. Miller Mark Steyvers University of California, Irvine
Getting Expert Information Delphi Method Iterative Collaboration
Independent Rank-Ordering Tasks Order these U.S. Presidents, by term of office: 1st Participant 2nd Participant 3rd Participant Thomas Jefferson Thomas Jefferson Thomas Jefferson John Adams John Adams George Washington John Adams James Monroe James Monroe James Madison George Washington James Monroe James Madison George Washington James Madison
Iterative Rank-Ordering Tasks Order these U.S. Presidents, by term of office: 1st Participant 2nd Participant 3rd Participant George Washington Thomas Jefferson George Washington James Madison John Adams Thomas Jefferson Thomas Jefferson James Monroe James Madison James Madison John Adams James Monroe James Monroe George Washington John Adams
Rank-Ordering Experiment • 100 Subjects • 17 Ranking Questions • Chronological Events (Holidays, U.S. Presidents) • Physical Measures (Landmass, City Pop., State Locations) • Ordinal Information (Ten Amendments, Ten Commandments) • 2 Conditions
Rank Ordering – Independent & Iteratives 17 Questions from University Students x 4 17 Questions via Mechanical Turk
Thurstonian Model for Rank Ordering A B C σ1 X13 X11 X12 Participant1 Y1: A < B < C
Thurstonian Model for Rank Ordering A B C σ2 X13 X11 X12 Participant1 Y1: A < B < C X23 X21 X22 Participant2 Y2 : A < C < B
Iterative Collaboration Position 33 34 35 36 37 38 39 Participants
Thurstonian Model for Item Representation A B C σ11 σ12 σ13 X13 X11 X12 Participant1 Y1: A < B < C
Rank-Ordering Experiment • 50 Subjects • 8 Ranking Questions • Chronological Events (Holidays, U.S. Presidents) • Physical Measures (Landmass, City Pop., State Locations) • Ordinal Information (Ten Amendments, Ten Commandments) Independent (8) Iterative (8) 7 5 6 4 1 8 3 2 7 5 6 4 1 8 3 2
Independent vs. Iterative Aggregate Performance Independent Iterative
Independent Subject Generative Model i Items μi µi ≡ Ground truth σ2ij ~ InvGamma(.2,1) xi ~ Norm(µi,σ2ij) Yj ~ Rank(xj) yj xij σij j Subjects
Iterative Subject Generative Model cut μij µi ≡ Ground truth σ2ij ~ InvGamma(.2,1) Xij-1 ~ Norm(µi,σ2ij-1) Yj-1 ~ Rank(xj-1) σi,j-1 σij yj yj-1 xi,j-1 xij i Items j Subjects
Reduction in Iterative Error by Item Confidence Confidence for Items with Error > 4 Tau No Change
Conclusions • Item-level knowledge may allow partial expertise between participants, allowing for improvement in group aggregation. • Subject item-level confidence appears to support the validity of our proposed model. • We should be able to use subjects’ confidence as an estimate of underlying item-level expertise.
Differences Between Observed and Latent Confidence in Rank Ordering Danke!