Click-through rate (CTR) is a key signal of relevance for search engine results, both organic and sponsored. CTR of a result has two core components: (a) the probability of examination of a result by a user, and (b) the perceived relevance of the result given that it has been examined by the user. There has been considerable work on user browsing models, to model and analyze both the examination and the relevance components of CTR. In this paper, we propose a novel formulation: a micro-browsing model for how users read result snippets. The snippet text of a result often plays a critical role in the perceived relevance of the result. We study how particular words within a line of snippet can influence user behavior. We validate this new micro-browsing user model by considering the problem of predicting which snippet will yield higher CTR, and show that classification accuracy is dramatically higher with our micro-browsing user model. The key insight in this paper is that varying relatively few words within a snippet, and even their location within a snippet, can have a significant influence on the clickthrough of a snippet.
Coupled logistic regression (CLR) @cite_6 uses all features from ad, user, context and nonlinear features such as conjunction information. It integrates the conjunction information by employing factorization machine to achieve precise CTR prediction result.
@cite_6
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Online advertisement is a significant element of the Web browsing experience. A good advertising can not only bring benefits to publisher but also improve user satisfaction and extends advertiser's product marketing. To satisfy the desire of all three parties, the click through rate (CTR) prediction of a user to a specified ad in a specific context is of great importance. This challenging problem plays a key role in online advertising system and has to deal with several hard issues. Firstly, the model must process very high dimensional features from frequently changing ad, user and context, most of which are category features having large cardinality and sparse nature extending the dimensionality by two orders of magnitude. Secondly, nonlinear features such as conjunction information must be integrated into the model for a better prediction accuracy. Finally, the model must be able to parallelized efficiently to train from very large scale data sets. To address these problems, we proposed a novel model called Coupled Logistic Regression (CLR), for accurate and efficient CTR prediction. CLR can exploit all features from ad, user, context and nonlinear features among them by seamlessly integrate the conjunction information by employing factorization machine to achieve precise prediction result. And the high-dimensional problem is avoided by decomposing the decision function into two sub ones. Scalability of CLR is ensured through a newly invited MapReduce parallelization strategy, which can reduce communication and waiting time between nodes. Experimental results on real-world data set show that our CLR model can guarantee both accuracy and efficiency on large scale CTR prediction problems. We investigate the use of logistic regression (LR) to initialise Reinforcement Learning (RL)-based dialogue systems with models of human dialogue strategies. LR produces accurate predictions and performs feature selection. We illustrate this technique in exploring human multimodal clarification strategies, observed in a Wizard-of-Oz experiment. We use it to initialise an RL-based system with features which significantly influence human behaviour. We show that the strategy applied by the human wizards is sensitive to different dialogue contexts. Furthermore we show that for predicting clarification behaviour the logistic models improve over the baseline on average twice as much as the supervised learning techniques used in previous work. Machine learning techniques such as classification and regression trees (CART) have been suggested as promising alternatives to logistic regression for the estimation of propensity scores. The authors examined the performance of various CART-based propensity score models using simulated data. Hypothetical studies of varying sample sizes (n=500, 1000, 2000) with a binary exposure, continuous outcome, and ten covariates were simulated under seven scenarios differing by degree of non-linear and non-additive associations between covariates and the exposure. Propensity score weights were estimated using logistic regression (all main effects), CART, pruned CART, and the ensemble methods of bagged CART, random forests, and boosted CART. Performance metrics included covariate balance, standard error, percent absolute bias, and 95 confidence interval coverage. All methods displayed generally acceptable performance under conditions of either non-linearity or non-additivity alone. However, under conditions of both moderate non-additivity and moderate non-linearity, logistic regression had subpar performance, while ensemble methods provided substantially better bias reduction and more consistent 95 CI coverage. The results suggest that ensemble methods, especially boosted CART, may be useful for propensity score weighting. The relationship between co-integration and error correction models, first suggested in Granger (1981), is here extended and used to develop estimation procedures, tests, and empirical examples.If each element of a vector of time series xt first achieves stationarity after differencing, but a linear combination α'xt, is already stationary, the time series xt are said to be co-integrated with co-integrating vector α. There may be several such co-integrating vectors so that α becomes a matrix. Interpreting α'xt, = 0 as a long run equilibrium, co-integration implies that deviations from equilibrium are stationary, with finite variance, even though the series themselves are nonstationary and have infinite variance.The paper presents a representation theorem based on Granger (1983), which connects the moving average, autoregressive, and error correction representations for co-integrated systems. A vector autoregression in differenced variables is incompatible with these representations. Estimation of these models is discussed and a simple but asymptotically efficient two-step estimator is proposed. Testing for co-integration combines the problems of unit root tests and tests with parameters unidentified under the null. Seven statistics are formulated and analyzed. The critical values of these statistics are calculated based on a Monte Carlo simulation. Using these critical values, the power properties of the tests are examined and one test procedure is recommended for application.In a series of examples it is found that consumption and income are co-integrated, wages and prices are not, short and long interest rates are, and nominal GNP is co-integrated with M2, but not M1, M3, or aggregate liquid assets.