Search result examination is an important part of searching. High page load latency for landing pages (clicked search results) can reduce the efficiency of the search process. Proactively prefetching landing pages in advance of clickthrough can save searchers valuable time. However, prefetching consumes resources (primarily bandwidth and battery) that are wasted unless the prefetched results are requested by searchers. Balancing the costs in prefetching particular results against the benefits in reduced latency to searchers represents the search result prefetching challenge. In this article, we introduce this challenge and present methods to address it in both desktop and mobile settings. Our methods leverage searchers’ cursor movements (on desktop) and viewport-based viewing behavior (on mobile) on search engine result pages (SERPs) in real time to dynamically estimate the result that searchers will request next. We demonstrate through large-scale log analysis that our approach significantly outperforms three strong baselines that prefetch results based on (i) the search engine result ranking (prefetch top-ranked results), (ii) past SERP clicks from all searchers for the query (prefetch popular results), or (iii) past SERP clicks from the current searcher for the query (prefetch results that the searcher prefers). Our promising findings have implications for the design of search support in desktop and mobile settings that makes the search process more efficient.

Search result examination is an important part of searching. High page load latency for landing pages (clicked results) can reduce the efficiency of the search process. Proactively prefetching landing pages in advance of clickthrough can save searchers valuable time. However, prefetching consumes resources that are wasted unless the prefetched results are requested by searchers. Balancing the costs in prefetching particular results against the benefits in reduced latency to searchers represents the search result prefetching challenge. We present methods that leverage searchers' cursor movements on search result pages in real time to dynamically estimate the result that searchers will request next. We demonstrate through large-scale log analysis that our approach significantly outperforms three strong baselines that prefetch results based on (i) the search engine result ranking, (ii) past clicks from all searchers for the query, or (iii) past clicks from the current searcher for the query. Our promising findings have implications for the design of search support that makes the search process more efficient.

Web search behavior and interaction data, such as mouse cursor movements, can provide valuable information on how searchers examine and engage with the web search results. This interaction data is far richer than traditional search click data, and can be used to improve search ranking, evaluation, and presentation. Unfortunately, the diversity and complexity inherent in this interaction data make it more difficult to capture salient behavior characteristics through traditional feature engineering. To address this problem, we introduce a novel approach of automatically discovering frequent subsequences, or motifs, in mouse cursor movement data. In order to scale our approach to realistic datasets, we introduce novel optimizations for motif discovery, specifically designed for mining cursor movement data. As a practical application, we show that by encoding the motifs discovered from thousands of real web search sessions as features, enables significant improvements on result relevance estimation and re-ranking tasks, compared to a state-of-the-art baseline that relies on extensive feature engineering. These results, complemented with visualization and qualitative analysis, demonstrate that our approach is able to automatically capture key characteristics of mouse cursor movement behavior, providing a valuable new tool for search behavior analysis.

Fine-grained search interactions in the desktop setting, such as mouse cursor movements and scrolling, have been shown valuable for understanding user intent, attention, and their preferences for Web search results. As web search on smart phones and tablets becomes increasingly popular, previously validated desktop interaction models have to be adapted for the available touch interactions such as pinching and swiping, and for the different device form factors. In this paper, we present, to our knowledge, the first in-depth study of modeling interactions on touch-enabled device for improving Web search ranking. In particular, we evaluate a variety of touch interactions on a smart phone as implicit relevance feedback, and compare them with the corresponding fine-grained interactions on a desktop computer with mouse and keyboard as the primary input devices. Our experiments are based on a dataset collected from two user studies with 56 users in total, using a specially instrumented version of a popular mobile browser to capture the interaction data. We report a detailed analysis of the similarities and differences of fine-grained search interactions between the desktop and the smart phone modalities, and identify novel patterns of touch interactions indicative of result relevance. Finally, we demonstrate significant improvements to search ranking quality by mining touch interaction data.

Detecting and predicting searcher success is essential for automatically evaluating and improving Web search engine performance. In the past, Web searcher behavior data, such as result clickthrough, dwell time, and query reformulation sequences, have been successfully used for a variety of tasks, including prediction of success in a search session. However, the effectiveness of the previous approaches has been limited, as they tend to ignore how searchers actually view and interact with the visited pages. We show that fine-grained interactions, such as mouse cursor movements and scrolling, provide additional clues for better predicting success of a search session as a whole. To this end, we identify patterns of examination and interaction behavior that correspond to search success, and design a new Fine-grained Session Behavior (FSB) model to capture these patterns. Our experimental results show that FSB is significantly more effective than the state-of-the-art approaches that do not use these additional interaction data.

Result clickthrough statistics and dwell time on clicked results have been shown valuable for inferring search result relevance, but the interpretation of these signals can vary substantially for different tasks and users. This paper shows that that post-click searcher behavior, such as cursor movement and scrolling, provides additional clues for better estimating document relevance. To this end, we identify patterns of examination and interaction behavior that correspond to viewing a relevant or non-relevant document, and design a new Post-Click Behavior (PCB) model to capture these patterns. To our knowledge, PCB is the first to successfully incorporate post-click searcher interactions such as cursor movements and scrolling on a landing page for estimating document relevance. We evaluate PCB on a dataset collected from a controlled user study that contains interactions gathered from hundreds of unique queries, result clicks, and page examinations. The experimental results show that PCB is significantly more effective than using page dwell time information alone, both for estimating the explicit judgments of each user, and for re-ranking the results using the estimated relevance.

A better understanding of strategies and behavior of successful searchers is crucial for improving the experience of all searchers. However, research of search behavior has been struggling with the tension between the relatively small-scale, but controlled lab studies, and the large-scale log-based studies where the searcher intent and many other important factors have to be inferred. We present our solution for performing controlled, yet realistic, scalable, and reproducible studies of searcher behavior. We focus on difficult informational tasks, which tend to frustrate many users of the current web search technology. First, we propose a principled formalization of different types of "success" for informational search, which encapsulate and sharpen previously proposed models. Second, we present a scalable game-like infrastructure for crowdsourcing search behavior studies, specifically targeted towards capturing and evaluating successful search strategies on informational tasks with known intent. Third, we report our analysis of search success using these data, which confirm and extends previous findings. Finally, we demonstrate that our model can predict search success more effectively than the existing state-of-the-art methods, on both our data and on a different set of log data collected from regular search engine sessions. Together, our search success models, the data collection infrastructure, and the associated behavior analysis techniques, significantly advance the study of success in web search.

Search engine switching is the voluntary transition between Web search engines. Engine switching can occur for a number of reasons, including user dissatisfaction with search results, a desire for broader topic coverage or verification, user preferences, or even unintentionally. An improved understanding of switching rationales allows search providers to tailor the search experience according to the different causes. In this paper we study the reasons behind search engine switching within a session. We address the challenge of identifying switching rationales by designing and implementing client-side instrumentation to acquire in-situ feedbacks from users. Using this feedback, we investigate in detail the reasons that users switch engines within a session. We also study the relationship between implicit behavioral signals and the switching causes, and develop and evaluate models to predict the reasons for switching. In addition, we collect editorial judgments of switching rationales by third-party judges and show that we can recover switching causes a posteriori. Our findings provide valuable insights into why users switch search engines in a session and demonstrate the relationship between search behavior and switching motivations. The findings also reveal sufficient behavioral consistency to afford accurate prediction of switching rationale, which can be used to dynamically adapt the search experience and derive more accurate competitive metrics.

Predicting searcher success and satisfaction is a key problem in Web search, which is essential for automatic evaluating and improving search engine performance. This problem has been studied actively in the desktop search setting, but not specifically for mobile search, despite many known differences between the two modalities. As mobile devices become increasingly popular for searching the Web, improving the searcher experience on such devices is becoming crucially important. In this paper, we explore the possibility of predicting searcher success and satisfaction in mobile search with a smart phone. Specifically, we investigate client-side interaction signals, including the number of browsed pages, and touch screen-specific actions such as zooming and sliding. Exploiting this information with machine learning techniques results in nearly 80% accuracy for predicting searcher success -- significantly outperforming the previous models.

An improved understanding of the relationship between search intent, result quality, and searcher behavior is crucial for improving the effectiveness of web search. While recent progress in user behavior mining has been largely focused on aggregate server-side click logs, we present a new class of search behavior models that also exploit fine-grained user interactions with the search results.

An improved understanding of the relationship between search intent, result quality, and searcher behavior is crucial for improving the effectiveness of web search. While recent progress in user behavior mining has been largely focused on aggregate server-side click logs, we present a new search behavior model that incorporates fine-grained user interactions with the search results. We show that mining these interactions, such as mouse movements and scrolling, can enable more effective detection of the user's search intent. Potential applications include automatic search evaluation, improving search ranking, result presentation, and search advertising. As a case study, we report results on distinguishing between "research" and "purchase" variants of commercial intent, that show our method to be more effective than the current state-of-the-art.

We describe preliminary results of experiments with an unsupervised framework for query segmentation, transforming keyword queries into structured queries. The resulting queries can be used to more accurately search product databases, and potentially improve result presentation and query suggestion. The key to developing an accurate and scalable system for this task is to train a query segmentation or attribute detection system over labeled data, which can be acquired automatically from query and click-through logs. The main contribution of our work is a new method to automatically acquire such training data - resulting in significantly higher segmentation performance, compared to previously reported methods.

Effective search session segmentation "grouping queries according to common task or intent" can be useful for improving relevance, search evaluation, and query suggestion. Previous work has largely attempted to segment search sessions off-line, after the fact. In contrast, we present preliminary investigation of predicting, in real time, whether a user is about to switch interest - that is, whether the user is about to finish the current search and switch to another search task (or stop searching altogether). We explore an approach for this task using client-side user behavior such as clicks, scrolls, and mouse movements, contextualized by the content of the search result pages and previous searches. Our experiments over thousands of real searches show that we can identify context and user behavior patterns that indicate that a user is about to switch to a new search task. These preliminary results can be helpful for more effective query suggestion and personalization.

Clickthrough rate, bid, and cost-per-click are known to be among the factors that impact the rank of an ad shown on a search result page. Search engines can benefit from estimating ad clickthrough in order to determine the quality of ads and maximize their revenue. In this paper, a methodology is developed to estimate ad clickthrough rate by exploring user queries and clickthrough logs. As we demonstrate, the average ad clickthrough rate depends to a substantial extent on the rank position of ads and on the total number of ads displayed on the page. This observation is utilized by a baseline model to calculate the expected clickthrough rate for various ads. We further study the impact of query intent on the clickthrough rate, where query intent is predicted using a combination of query features and the content of search engine result pages. The baseline model and the query intent model are compared for the purpose of calculating the expected ad clickthrough rate. Our findings suggest that such factors as the rank of an ad, the number of ads displayed on the result page, and query intent are effective in estimating ad clickthrough rate.

We present a method for modeling, and automaticallyinferring, the current interest of a user in searchadvertising. Our task is complementary to that of predictingad relevance or commercial intent of a query in the aggregate, since the user intent may vary significantly for the same query. To achieve this goal, we develop a fine-grained user interaction model for inferring searcher receptiveness to advertising. We show that modeling the search context and behavior can significantly improve the accuracy of ad clickthrough prediction for the current user, compared to the existing state-of-the-artclassification methods that do not model this additional session level contextual and interaction information. In particular, our experiments over thousands of search sessions from hundreds of real users demonstrate that our model is more effective at predicting ad clickthrough within the same search session. Our work has other potential applications, such as improving searchinterface design (e.g., varying the number or type of ads) based on user interest, and behavioral targeting (e.g., identifying users interested in immediate purchase).

Clickthrough on search results have been successfully used to infer user interest and preferences, but are often noisy and potentially ambiguous. We explore the potential of a complementary, more sensitive signal -mouse movements- in providing insights into the intent behind a web search query. We report preliminary results of studying user mouse movements on search result pages, with the goal of inferring user intent - in particular, to explore whether we can automatically distinguish the different query classes such as navigational vs. informational. Our preliminary exploration confirms the value of studying mouse movements for user intent inference, and suggests interesting avenues for future exploration.