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Measurement Problems (measurement + problem)
Selected AbstractsAssessing the Validity of Insurance Coverage Data in Hospital Discharge Records: California OSHPD DataHEALTH SERVICES RESEARCH, Issue 5 2003Thomas C. Buchmueller Objective. To assess the accuracy of data on "expected source of payment" in the patient discharge database compiled by the California Office of Statewide Health Planning and Development (OSHPD). Data Sources. The OSHPD discharge data for the years 1993 to 1996 linked with administrative data from the University of California (UC) health benefits program for the same years. The linked dataset contains records for all stays in California hospitals by UC employees, retirees, and spouses. Study Design. The accuracy of the OSHPD data is assessed using cross-tabulations of insurance type as coded in the two data sources. The UC administrative data is assumed to be accurate, implying that differences between the two sources represent measurement error in the OSHPD data. We cross-tabulate insurance categories and analyze the concordance of dichotomous measures of health maintenance organization (HMO) enrollment derived from the two sources. Principal Findings. There are significant coding errors in the OSHPD data on expected source of payment. A nontrivial percentage of patients with preferred provider organization (PPO) coverage are erroneously coded as being in HMOs, and vice versa. The prevalence of such errors increased after OSHPD introduced a new expected source of payment category for PPOs. Measurement problems are especially pronounced for older patients. Many patients over age 65 who are still covered by a commercial insurance plan are erroneously coded as having Medicare coverage. This, combined with the fact that during the period we analyzed, Medicare HMO enrollees and beneficiaries in the fee-for-service (FFS) program are combined in a single payment category, means that the OSHPD data provides essentially no information on insurance coverage for older patients. Conclusions. Researchers should exercise caution in using the expected source of payment in the OSHPD data. While measures of HMO coverage are reasonably accurate, it is not possible in these data to clearly identify PPOs as a distinct insurance category. For patients over age 65, it is not possible at all to distinguish among alternative insurance arrangements. [source] Constituents' Responses to Congressional Roll-Call VotingAMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 3 2010Stephen Ansolabehere Do citizens hold their representatives accountable for policy decisions, as commonly assumed in theories of legislative politics? Previous research has failed to yield clear evidence on this question for two reasons: measurement error arising from noncomparable indicators of legislators' and constituents' preferences and potential simultaneity between constituents' beliefs about and approval of their representatives. Two new national surveys address the measurement problem directly by asking respondents how they would vote and how they think their representatives voted on key roll-call votes. Using the actual votes, we can, in turn, construct instrumental variables that correct for simultaneity. We find that the American electorate responds strongly to substantive representation. (1) Nearly all respondents have preferences over important bills before Congress. (2) Most constituents hold beliefs about their legislators' roll-call votes that reflect both the legislators' actual behavior and the parties' policy reputations. (3) Constituents use those beliefs to hold their legislators accountable. [source] The Dynamic Relation Between Returns and Idiosyncratic VolatilityFINANCIAL MANAGEMENT, Issue 2 2006Xiaoquan Jiang We claim that regressing excess returns on one-lagged volatility provides only a limited picture of the dynamic effect of idiosyncratic risk, which tends to be persistent over time. By correcting for the serial correlation in idiosyncratic volatility, we find that idiosyncratic volatility has a significant positive effect. This finding seems robusrt for various firm size portfolios, sample periods, and measures of idiosyncratic risk. Our findings suggest stock markets mis-price idiosyncratic risk. There may be some measurement problems with idiosyncratic risk. There may be some measurement problems with idiosyncratic risk that could be related to nondiversifiable risk. [source] Public Provision for Urban Water: Getting Prices and Governance RightGOVERNANCE, Issue 4 2008EDUARDO ARARAL Public sector monopolies are often associated with inefficiencies and inability to meet rising demand. Scholars attribute this to fundamental problems associated with public provision: (1) a tradition of below-cost pricing due to populist pressures, (2) owner,regulator conflicts of interest, and (3) perverse organizational incentives arising from non-credible threat of bankruptcy, weak competition, rigidities, and agency and performance measurement problems. Many governments worldwide have shifted to private provision, but recent experience in urban water utilities in developing countries has shown their limitations because of weak regulatory regimes compounded by inherent problems of information, incentives, and commitment. This article examines the paradoxical case of the Phnom Penh Water Supply in Cambodia to illustrate how public provision of urban water can be substantially improved by getting prices and governance right. Findings have implications for the search for solutions to provide one billion people worldwide with better access to potable water. [source] General and Specific Issues for Researchers' Consideration in Applying the Risk and Resilience Framework to the Social Domain of Learning DisabilitiesLEARNING DISABILITIES RESEARCH & PRACTICE, Issue 2 2003Bernice Y. L. Wong In this article, I discuss several general and specific issues that pertain to the risk and resilience framework. I propose that these issues deserve consideration by researchers using or interested in using the risk and resilience framework to guide their research in the social domain of learning disabilities. General issues discussed include: (1) integrating current research findings with those from prior longitudinal research by Emmy Werner and her associates, and from research in the 1980s and 1990s on problems in social perception and communication in children with learning disabilities; (2) measurement problems; and (3) the need for more differentiation in research regarding gender and the severity of learning disabilities. The specific issues discussed include: the need to continue to search for potential risk and protective factors; the need to research mediating processes or mechanisms that render a factor a risk or a protection; and the nature of intervention research. [source] GROWTH AND MEASUREMENT UNCERTAINTY IN AN UNREGULATED FISHERYNATURAL RESOURCE MODELING, Issue 3 2009ANNE B. JOHANNESEN Abstract Complete information is usually assumed in harvesting models of marine and terrestrial resources. In reality, however, complete information never exists. Fish and wildlife populations often fluctuate unpredictably in numbers, and measurement problems are frequent. In this paper, we analyze a time-discrete fishery model that distinguishes between uncertain natural growth and measurement error and in which exploitation takes place in an unregulated manner. Depending on the parameterization of the model and at which point of time uncertainty is resolved, it is shown that expected harvest under ecological uncertainty may be below or above that of the benchmark model with no uncertainty. On the other hand, when stock measurement is uncertain, expected harvest never exceeds the benchmark level. We also demonstrate that the harvesting profit, or rent, under uncertainty may be above that of the benchmark situation of complete information. In other words, less information may be beneficial for the fishermen. [source] The Productivity Impact of IT Deployment: An Empirical Evaluation of ATM IntroductionOXFORD BULLETIN OF ECONOMICS & STATISTICS, Issue 5 2000Michelle Haynes The term ,IT paradox' has been widely used to describe the apparent failure of much economic research to discover significant productivity gains associated with IT investment. In part this has been ascribed to measurement problems associated with both IT inputs and with outputs in IT-intensive industries. The current paper seeks to circumvent these difficulties by taking the ATM as a clearly defined embodied IT application and then using anaugmented production function approach to isolate its productivity effectsacross a sample of UK building societies, over the period of the ATM'sdiffusion. The paper finds no support for the ,IT paradox' and reports large robust and statistically significant productivity gains associated with ATM introduction. [source] Estimating Returns on Commercial Real Estate: A New Methodology Using Latent-Variable ModelsREAL ESTATE ECONOMICS, Issue 2 2000David C. Ling Despite their widespreao use as benchmarks of U.S. commercial real estate returns, indexes produced by the National Council of Real Estate Investment Fiduciaries (NCREIF) are subject to measurement problems that severely impair their ability to capture the true risk,return characteristics,especially volatility,of privately held commercial real estate. We utilize latent-variable statistical methods to estimate an alternative index of privately held (unsecuritized) commercial real estate returns. Latent-variable methods have been extensively applied in the behavioral sciences and, more recently, in finance and economics. Unlike factor analysis or other unconditional statistical approaches, latent variable models allow us to extract interpretable common information about unobserved private real estate returns using the information contained in various competing measures of returns that are measured with error. We find that our latent-variable real estate return series is approximately twice as volatile as the aggregate NCREIF total return index, but less than half as volatile as the NAREIT equity index. Overall, our results strongly support the use of latent-variable statistical models in the construction of return series for commercial real estate. [source] Estimation of a residual distribution with small numbers of repeated measurementsTHE CANADIAN JOURNAL OF STATISTICS, Issue 3 2002Edward Susko Abstract The authors consider the estimation of a residual distribution for different measurement problems with a common measurement error process. The problem is motivated by issues arising in the analysis of gene expression data but should have application in other similar settings. It is implicitly assumed throughout that there are large numbers of measurements but small numbers of repeated measurements. As a consequence, the distribution of the estimated residuals is a biased estimate of the residual distribution. The authors present two methods for the estimation of the residual distribution with some restriction on the form of the distribution. They give an upper bound for the rate of convergence for an estimator based on the characteristic function and compare its performance with that of another estimator with simulations. Estimation de la loi des erreurs à partir d'un petit nombre de mesures répétées Les auteurs s' intéressent à l' estimation d' une loi des erreurs supposée commune à un ensemble de situations expérimentales. Leur préoccupation émane de problèmes concernant l' analyse de l' expression des génes, mais la méthodologie qu' ils proposent a une portée plus large. Leur technique suppose l' accés à un grand nombre de données mais à un petit nombre de mesures répétées. La loi des résidus constitue alors un estimateur biaisé de celle des erreurs. Les auteurs présentent deux méthodes d' estimation de cette dernière, sous certaines hypothèses quant à sa forme. Us majorent le taux de convergence d' un premier estimateur dérivé de la fonction caractéristique et comparent sa performance à celle d' un second au moyen de simulations. [source] Implementing a strategy-driven performance measurement system for an applied research groupTHE JOURNAL OF PRODUCT INNOVATION MANAGEMENT, Issue 3 2002Christoph H. Loch Although most companies recognize the importance of R&D for future competitiveness, they often struggle to assess its contribution to the organization. Performance measurement in R&D is particularly difficult because (1) effort levels may not be observable, (2) project success is uncertain, influenced by uncontrollable factors, and (3) success can be assessed only after long delays, or it accrues to other units of the organization. Based on existing literature on the problem, we developed a performance measurement system for the process technology research group of an industrial company. This measurement system systematically supported the business strategy. Moreover, the measures were adjusted for different project profiles: short-versus long term, hardware versus software, routine support services versus breakthrough ideas and knowledge development. The contribution of this article is a description of the process of developing and implementing a comprehensive performance measurement system in a company, based on previous performance management research, and supporting the company's strategy. It is noteworthy that the system was implemented in a research group (as opposed to development), where the measurement problems are the most severe. [source] | ||||||||||||||||