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In the Mood to Click? Towards Inferring Receptiveness to Search Advertising. WI 2009. Outline. Introduction Define Contextualized Interaction model Modeling and classifier implementation Experiment Conclusion and future work. Introduction. Goal: Select the “right time” to serve an ad.
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In the Mood to Click? Towards Inferring Receptiveness to Search Advertising WI 2009
Outline • Introduction • Define • Contextualized Interaction model • Modeling and classifier implementation • Experiment • Conclusion and future work
Introduction • Goal: Select the “right time” to serve an ad. • Interaction feature: ex: mouse movements, clicks, page scrolls.
Define(1/3) • Search session: a sequence which is no time gap of greater than 30 minutes between any two consecutive searches. • Search mission: (within a session) a query of each search shares at least one non-stopword query term with at least one previous (but not necessarily consecutive) query.
Define(3/3) • S(s1,…,si,…,sm): search mission • Predicting Advertising Receptiveness: predict whether the searcher will click on an ad presented on the results for any of the future searches si+1,si+2,…,sm within the current search mission S. • Reduce to searcher receptiveness: clickthrough of search engines is low (google CTR in dataset is about 1%)
CxI system CxI(Contextualized Interaction model) • Data collection: use LibX toolbar
CxI - Features(1/2) • Context features: query, clicked URL, page content, number of ads… • Interaction features: time before first move, dwell time, the ways of entering the page(issue a new query or “back” button) • Global features: length, vertical and horizontal ranges of trajectories
CxI - Features(2/2) • Trajectory features: speed, acceleration, rotation of mouse movement • Hovering features: hovering over the ad regions on pages(boolean features) • Ad clickthrough features: ad clickthrough on current page
Two modeling approaches • Page-Level(stateless) Model: predict for each query, then combine predictions to classify the mission as receptive or not • Session-Level contextual Model: infer the most likely sequence of hidden states and predict future ad clickthrough
Classifier implementation • Page-level classification: use Support Vector Machines • Session-level classification: use CRF(Condictional Random Fields)
CRF of Session-Level Model • R: Receptive/Expect Ad Click in future search in the mission • N: Do Not Expect Ad Click in future search
Experiment(1/5) • Dataset: • The data was gathered from 8/15 through 12/15 2008 • 440 users who have clicked on a search ad at least once • 6576 search sessions, 17123 search missions and 45212 searches
Experiment(2/5) • Metrics • Precision(P): fraction of True Positive over all predicted positives in the mission • Recall(R): fraction of correct positive predictions(TP) over all positive labels in the mission • F1-measure(F1): 2*P*R / (P+R)
Experiment(3/5) Methods compared • QC(Query Chains):using query strings, page URLs… • QCLK: clicked URL • PC(Page-level Context) • CxI(C): using context features • CxI(C+I): using context features and interation features
Experiment(4/5) • 80% of the sessions for training, 20% for testing(5-fold Cross Validation)
Experiment(5/5) • Copy positive training samples five times • Assign higher weight to positive class Substantial improvement on P and F1
Conclusion And Future Work • Present new model for predicting ad clickthrough on search ads • Hypothesize the existence of “hidden state” which corresponds to ad receptiveness of user • Add personal user history