计量经济分析 = Econometric analysis

25. Multiple Imputation for Nonresponse in Surveys. By D. B. Rubin. ISBN 0 471 08705 X. Wiley, Chichester, 1987. 258 pp. £30.25.

Multiple Imputation for Nonresponse in Surveys

We discuss a method for improving causal inferences called ‘‘Coarsened Exact Matching’’ (CEM), and the new ‘‘Monotonic Imbalance Bounding’’ (MIB) class of matching methods from which CEM is derived. We summarize what is known about CEM and MIB, derive and illustrate several new desirable statistical properties of CEM, and then propose a variety of useful extensions. We show that CEM possesses a wide range of statistical properties not available in most other matching methods but is at the same time exceptionally easy to comprehend and use. We focus on the connection between theoretical properties and practical applications. We also make available easy-to-use open source software for R, Stata, and SPSS that implement all our suggestions.

/pdf/causal-inference-without-balance-checking-coarsened-exact-1xeumfa548.pdf

Causal Inference without Balance Checking: Coarsened Exact Matching

We explore the effect of dimensionality on the nearest neighbor problem. We show that under a broad set of conditions (much broader than independent and identically distributed dimensions), as dimensionality increases, the distance to the nearest data point approaches the distance to the farthest data point. To provide a practical perspective, we present empirical results on both real and synthetic data sets that demonstrate that this effect can occur for as few as 10-15 dimensions. These results should not be interpreted to mean that high-dimensional indexing is never meaningful; we illustrate this point by identifying some high-dimensional workloads for which this effect does not occur. However, our results do emphasize that the methodology used almost universally in the database literature to evaluate high-dimensional indexing techniques is flawed, and should be modified. In particular, most such techniques proposed in the literature are not evaluated versus simple linear scan, and are evaluated over workloads for which nearest neighbor is not meaningful. Often, even the reported experiments, when analyzed carefully, show that linear scan would outperform the techniques being proposed on the workloads studied in high (10-15) dimensionality!.

When is nearest neighbor meaningful

Contrasting treatment‐specific survival using double‐robust estimators

Matching methods for causal inference selectively prune observations from the data in order to reduce model dependence. They are successful when simultaneously maximizing balance (between the treated and control groups on the pre-treatment covariates) and the number of observations remaining in the data set. However, existing matching methods either fix the matched sample size ex ante and attempt to reduce imbalance as a result of the procedure (e.g., propensity score and Mahalanobis distance matching) or fix imbalance ex ante and attempt to lose as few observations as possible ex post (e.g., coarsened exact matching and calpier-based approaches). As an alternative, we offer a simple graphical approach that addresses both criteria simultaneously and lets the user choose a matching solution from the imbalancesample size frontier. In the process of applying our approach, we also discover that propensity score matching (PSM) often approximates random matching, both in real applications and in data simulated by the processes that fit PSM theory. Moreover, contrary to conventional wisdom, random matching is not benign: it (and thus often PSM) can degrade inferences relative to not matching at all. Other methods we study do not have these or other problems we describe. However, with our easy-to-use graphical approach, users can focus on choosing a matching solution for a particular application rather than whatever method happened to be used to generate it.

/pdf/comparative-effectiveness-of-matching-methods-for-causal-12oti7fpxy.pdf

Comparative Effectiveness of Matching Methods for Causal Inference

Employers struggle with the high cost of health care, lost productivity, and turnover in their workforce The present study aims to understand the association between overall well-being an

http://info.healthways.com/hubfs/Science_and_Research/overall-well-being.pdf?t=1435786053789

Overall well-being as a predictor of health care, productivity, and retention outcomes in a large employer.

Background 
Macrophages provide an interface between innate and adaptive immunity and are important long-lived reservoirs for Human Immunodeficiency Virus Type-1 (HIV-1). Multiple genetic networks involved in regulating signal transduction cascades and immune responses in macrophages are coordinately modulated by HIV-1 infection.


Methodology/Principal Findings 
To evaluate complex interrelated processes and to assemble an integrated view of activated signaling networks, a systems biology strategy was applied to genomic and proteomic responses by primary human macrophages over the course of HIV-1 infection. Macrophage responses, including cell cycle, calcium, apoptosis, mitogen-activated protein kinases (MAPK), and cytokines/chemokines, to HIV-1 were temporally regulated, in the absence of cell proliferation. In contrast, Toll-like receptor (TLR) pathways remained unaltered by HIV-1, although TLRs 3, 4, 7, and 8 were expressed and responded to ligand stimulation in macrophages. HIV-1 failed to activate phosphorylation of IRAK-1 or IRF-3, modulate intracellular protein levels of Mx1, an interferon-stimulated gene, or stimulate secretion of TNF, IL-1β, or IL-6. Activation of pathways other than TLR was inadequate to stimulate, via cross-talk mechanisms through molecular hubs, the production of proinflammatory cytokines typical of a TLR response. HIV-1 sensitized macrophage responses to TLR ligands, and the magnitude of viral priming was related to virus replication.


Conclusions/Significance 
HIV-1 induced a primed, proinflammatory state, M1HIV, which increased the responsiveness of macrophages to TLR ligands. HIV-1 might passively evade pattern recognition, actively inhibit or suppress recognition and signaling, or require dynamic interactions between macrophages and other cells, such as lymphocytes or endothelial cells. HIV-1 evasion of TLR recognition and simultaneous priming of macrophages may represent a strategy for viral survival, contribute to immune pathogenesis, and provide important targets for therapeutic approaches.

HIV-1 Activates Macrophages Independent of Toll-Like Receptors

The objective of this study is to identify the contribution that selected demographic characteristics, health behaviors, physical health outcomes, and workplace environmental factors have on presenteeism (on-the-job productivity loss attributed to poor health and other personal issues). Analyses are based on a cross-sectional survey administered to 3 geographically diverse US companies in 2010. Work-related factors had the greatest influence on presenteeism (eg, too much to do but not enough time to do it, insufficient technological support/resources). Personal problems and financial stress/concerns also contributed substantially to presenteeism. Factors with less contribution to presenteeism included physical limitations, depression or anxiety, inadequate job training, and problems with supervisors and coworkers. Presenteeism was greatest for those ages 30–49, women, separated/divorced/widowed employees, and those with a high school degree or some college. Clerical/office workers and service wor...

Presenteeism According to Healthy Behaviors, Physical Health, and Work Environment

Objective: To better understand the combined influence of employee engagement, health behavior, and physical health on job performance and absenteeism. Methods: Analyses were based on 20,114 employees who completedtheHealthwaysWell-BeingAssessmentfrom2008to2010.Employees represented three geographically dispersed companies in the United States. Results: Employee engagement, health behavior, and physical health indices were simultaneously significantly associated with job performance and also with absenteeism. Employee engagement had a greater association with job performance than did the health behavior or physical health indices, whereas the physical health index was more strongly associated with absenteeism. Specificelementsoftheindiceswereevaluatedforassociationwithself-rated job performance and absenteeism. Conclusion: Efforts to improve worker productivity should take a holistic approach encompassing employee health improvement and engagement strategies.

http://info.healthways.com/hubfs/Science_and_Research/Self-rated-job-performance.pdf?t=1441383706833

Carter Coberley

Papers

Comparative Effectiveness of Matching Methods for Causal Inference

Overall well-being as a predictor of health care, productivity, and retention outcomes in a large employer.

HIV-1 Activates Macrophages Independent of Toll-Like Receptors

Presenteeism According to Healthy Behaviors, Physical Health, and Work Environment

Self-Rated Job Performance and Absenteeism According to Employee Engagement, Health Behaviors, and Physical Health