Consumer Heterogeneity and Paid Search Effectiveness: A Large‐Scale Field Experiment

Internet advertising has been the fastest growing advertising channel in recent years, with paid search ads comprising the bulk of this revenue. We present results from a series of large‐scale field experiments done at eBay that were designed to measure the causal effectiveness of paid search ads. Because search clicks and purchase intent are correlated, we show that returns from paid search are a fraction of non‐experimental estimates. As an extreme case, we show that brand keyword ads have no measurable short‐term benefits. For non‐brand keywords, we find that new and infrequent users are positively influenced by ads but that more frequent users whose purchasing behavior is not influenced by ads account for most of the advertising expenses, resulting in average returns that are negative.     

Envisioning emerging nanotechnologies: a three-year panel study of South Carolina citizens

This article reports results from a three-year panel study of a nonrandom sample of 76 South Carolina citizens, recruited from a variety of walks of life, and their impressions of emerging nanotechnology. This discussion focuses on material from depth interviews conducted alongside a baseline opinion and awareness inventory at the beginning of the study, the most intensive data-gathering phase. These results are placed in the context of data from three additional surveys conducted at about equal intervals over the three years, plus exit interviews from 21 of the 34 individuals who completed the entire study. The results give insight into popular thinking about technology but little indication of strong emerging concerns, a trajectory of amplification of those concerns, or opinion polarization over time, despite some awareness of risks and potential ethical dimensions. Nanotechnology may stand out more as an example of risk attenuation than of risk amplification, consistent with most results from national surveys.     

The research frontier in corporate governance

In this paper we attempt to identify the research frontier in corporate governance using three different approaches: (1) what challenges does the financial crisis 2007–2009 pose for corporate governance research? We show that the financial crisis is a huge natural experiment which has exposed gaps in our knowledge of corporate governance and is likely to lead of a rethink of central concepts like shareholder value, debt governance, and management incentives (2) what do we know and what do we need to how about the impact of national institutions on corporate governance? (3) What research questions are raised by a focus on current corporate governance practices?     

Decoding the Miss Daisy Syndrome: an examination of subjective responses to mobility change

The subjective responses associated with personal life space and mobility status were explored. Thirty individuals participated in focus groups based on self-rated disability status, current places visited, and availability. Qualitative analyses revealed that most participants equated personal mobility with driving a vehicle. Attitudes concerning mobility status and preparedness for change varied based on disability level and personal experience. Fear of dependence from future mobility loss was prominent in all groups. Few participants acknowledged significant planning for future retirement from driving or other mobility challenges. An understanding of common attitudes, perceptions and meanings can inform professionals who intervene and support older adults experiencing mobility changes.     

Dynamics of social assistance: the Norwegian experience in comparative perspective

In the article we ask how long Norwegian recipients of social assistance stay on aid over an eight‐year period? We focus on the populations selected, the design of the study and how spells are recorded and measured. The data set includes nearly the entire 1995 cohort of social assistance claimants (n = 155,000), and contains individual information over eight years (1992–1999), which is the maximum length of a single continuous spell. The study combines a retrospective and a prospective multiple cohort design. The data analysis shows that there is no simple answer to our question; the answer depends on the sample selected, the design, number of spells counted and the chosen measure of central tendency. We find that median duration times vary from two months to 40 months. The conclusion is that a point‐in‐time sample has clearly the longest duration. It makes a big difference whether one measures one or more spells. Because cycling is a common phenomenon, the sum of all spell durations is much higher than that of the first continuous spell. A retrospective design severely underestimates spell durations since many spells are right‐hand censored. As there is no single, adequate answer to our initial question, it is recommended that analysts of social assistance dynamics carefully specify their sample, design and spells counted.     

Economic concentration and corporate political behavior: A cross-industry comparison

Several political sociologists have argued that the trend toward economic concentration in major industries in advanced capitalist societies has led to a growth in corporate political power. Most of these arguments are based on the notion that economic concentration facilitates the mobilization of industries as cohesive politica actors. This paper presents an empirical examination of this argument. The similarity of campaign contributions in the 1980 Congressional elections by the four largest members of 25 industries is employed as the dependent variable. Concentration ratios within the industries, sizes and geographical proximities of the firms, and measures of within-industry economic and social integration are employed as independent and intervening variables. Employing a spatial autocorrelation model to correct for nonindependence among observations, we find that although concentration and similarity of political behavior are positively associated in a bivariate correlation, the relation disappears when controls are introduced. Common stock ownership by the same institutions and indirect director interlocks through financial institutions are significant predictors of behavioral similarity.     

Greater Downside Risk Aversion

Although investors are concerned foremost with mean and variance, they are also sensitive to downside risk. In this paper, we introduce an index of downside risk aversion to distinguish risk aversion from higher-order aspects of risk preference, including prudence. We show that the index of downside risk aversion S increases with monotonic downside risk averse transformations of utility, thereby directly linking S to the definition of downside risk aversion introduced by Menezes et al. (American Economic Review, 70, 921–932, 1980). Although the index S applies equally to risk averse and risk loving decision makers, for a given positive degree of risk aversion, S is greater when the index of prudence is greater and vice versa.     

Shape-constrained Gaussian process regression for surface reconstruction and multimodal,non-rigid image registration

We present a new statistical framework for landmark ?>curve-based image registration and surface reconstruction. The proposed method first elastically aligns geometric features (continuous, parameterized curves) to compute local deformations, and then uses a Gaussian random field model to estimate the full deformation vector field as a spatial stochastic process on the entire surface or image domain. The statistical estimation is performed using two different methods: maximum likelihood and Bayesian inference via Markov Chain Monte Carlo sampling. The resulting deformations accurately match corresponding curve regions while also being sufficiently smooth over the entire domain. We present several qualitative and quantitative evaluations of the proposed method on both synthetic and real data. We apply our approach to two different tasks on real data: (1) multimodal medical image registration, and (2) anatomical and pottery surface reconstruction.     

The impact of remittances from Canada's seasonal workers programme on Mexican farms

Based on a survey of participants in Canada's Seasonal Agricultural Workers Program, the authors’ three‐stage least squares estimation of a simultaneous equation model finds that migrants’ remittances enhance on‐farm investments in Mexico, which, in turn, increase farm income. Remittances are also found to have a positive influence on non‐farm income in Mexico, by giving respondents the possibility of starting a new business and diversifying their investments. These results support the hypothesis underlying the “new economics of labour migration” that remittances contribute to economic development by relaxing the credit constraint on the investment function of family farms.     

Response to “Becoming Visible: The Case of Collette”

The clinician’s experiences of race outside of the treatment room contribute to the formation of a racialized self, which influences clinical work with all clients notwithstanding race. Multiracial individuals at times must balance their external physical presentation—and the corresponding race-related categories that others place on them—with their own internally constructed racial identifications. The mechanisms of identification and disidentification can provide safety for the multiracial individual. How can clinicians effectively acknowledge their own identifications and disidentifications as lenses for seeing the multiracial person’s racialized self and selves so as to more effectively work with the multiracial?