Long queries form a difficult, but increasingly important segment for web search engines. Query reduction, a technique for dropping unnecessary query terms from long queries, improves performance of ad-hoc retrieval on TREC collections. Also, it has great potential for improving long web queries (upto 25% improvement in NDCG@5). However, query reduction on the web is hampered by the lack of accurate query performance predictors and the constraints imposed by search engine architectures and ranking algorithms.In this paper, we present query reduction techniques for long web queries that leverage effective and efficient query performance predictors. We propose three learning formulations that combine these predictors to perform automatic query reduction. These formulations enable trading off average improvements for the number of queries impacted, and enable easy integration into the search engine's architecture for rank-time query reduction. Experiments on a large collection of long queries issued to a commercial search engine show that the proposed techniques significantly outperform baselines, with more than 12% improvement in NDCG@5 in the impacted set of queries. Extension to the formulations such as result interleaving further improves results. We find that the proposed techniques deliver consistent retrieval gains where it matters most: poorly performing long web queries.
This paper examines how the enforceability of noncompete covenants affects the creation, growth, and survival of spinouts and other new entrants. The impact of noncompete enforceability on new firms is ambiguous, since noncompetes reduce knowledge leakage but impose hiring costs. However, we posit that enforceability screens formation of within-industry spinouts (WSOs) relative to non-WSOs by dissuading founders with lower human capital. Using data on 5.5 million new firms, we find greater enforceability is associated with fewer WSOs, but relative to non-WSOs, WSOs that are created tend to start and stay larger, are founded by higher-earners, and are more likely to survive their initial years. In contrast, we find no impact on non-WSO entry and a negative effect on size and short-term survival. The online appendix is available at https://doi.org/10.1287/mnsc.2016.2614 . This paper was accepted by David Hsu, entrepreneurship and innovation.
Research summaryUsing a productivity technique (VCA model), we estimate the economic value created by a firm and appropriated by its stakeholders in two specific empirical contexts. In the first application, we use publicly available data from the US airline industry to illustrate how the VCA model can be used with multiple stakeholder groups. In the second application, we provide estimates for three global automobile companies (GM, Toyota and Nissan), showing how the model can be reformulated using value added. In both industries we find substantial heterogeneity among firms in the creation and distribution of value. We discuss strengths and limitations of the VCA model and implications for strategic management research.
Managerial summaryFirms create value not only for shareholders, but also for other stakeholders, including employees, customers and suppliers. This article applies a method to quantify the "new" economic value created by a firm over an interval of time; the method also reveals the distribution of that value among the stakeholders. The proposed method gives managers some means to assess changes in the economic value created and distributed. We find that the creation and distribution of value has varied greatly among major US airlines and global automakers in recent decades. Moreover, returns to shareholders typically accounted for only a small proportion of firms' total value creation and often had little relation to broader changes in the magnitude and distribution of value.2
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.