Narrow your search
Listing 1 - 10 of 145 << page
of 15
>>
Sort by

Book
Instrumental Variables Estimation of Average Treatment Effects in Econometrics and Epidemiology
Authors: ---
Year: 1991 Publisher: Cambridge, Mass. National Bureau of Economic Research

Loading...
Export citation

Choose an application

Bookmark

Abstract

The average effect of intervention or treatment is a parameter of interest in both epidemiology and econometrics. A key difference between applications in the two fields is that epidemiologic research is more likely to involve qualitative outcomes and nonlinear models. An example is the recent use of the Vietnam era draft lottery to construct estimates of the effect of Vietnam era military service on civilian mortality. In this paper. I present necessary and sufficient conditions for linear instrumental variables. techniques to consistently estimate average treatment effects in qualitative or other nonlinear models. Most latent index models commonly applied to qualitative outcomes in econometrics fail to satisfy these conditions, and monte carlo evidence on the bias of instrumental estimates of the average treatment effect in a bivariate probit model is presented. The evidence suggests that linear instrumental variables estimators perform nearly as well as the correctly specified maximum likelihood estimator. especially in large samples. Linear instrumental variables and the normal maximum likelihood estimator are also remarkably robust to non-normality.


Book
Inference with Weak Instruments
Authors: --- ---
Year: 2005 Publisher: Cambridge, Mass. National Bureau of Economic Research

Loading...
Export citation

Choose an application

Bookmark

Abstract

This paper reviews recent developments in methods for dealing with weak instruments (IVs) in IV regression models. The focus is more on tests and confidence intervals derived from tests than on estimators. The paper also presents new testing results under "many weak IV asymptotics," which are relevant when the number of IVs is large and the coefficients on the IVs are relatively small. Asymptotic power envelopes for invariant tests are established. Power comparisons of the conditional likelihood ratio (CLR), Anderson- Rubin, and Lagrange multiplier tests are made. Numerical results show that the CLR test is on the asymptotic power envelope. This holds no matter what the relative magnitude of the IV strength to the number of IVs.


Book
Monotone Instrumental Variables with an Application to the Returns to Schooling
Authors: --- ---
Year: 1998 Publisher: Cambridge, Mass. National Bureau of Economic Research

Loading...
Export citation

Choose an application

Bookmark

Abstract

Econometric analyses of treatment response commonly use instrumental variable (IV) assumptions to identify treatment effects. Yet the credibility of IV assumptions is often a matter of considerable disagreement, with much debate about whether some covariate is or is not a "valid instrument" in an application of interest. There is therefore good reason to consider weaker but more credible assumptions. assumptions. To this end, we introduce monotone instrumental variable (MIV) A particularly interesting special case of an MIV assumption is monotone treatment selection (MTS). IV and MIV assumptions may be imposed alone or in combination with other assumptions. We study the identifying power of MIV assumptions in three informational settings: MIV alone; MIV combined with the classical linear response assumption; MIV combined with the monotone treatment response (MTR) assumption. We apply the results to the problem of inference on the returns to schooling. We analyze wage data reported by white male respondents to the National Longitudinal Survey of Youth (NLSY) and use the respondent's AFQT score as an MIV. We find that this MIV assumption has little identifying power when imposed alone. However combining the MIV assumption with the MTR and MTS assumptions yields fairly tight bounds on two distinct measures of the returns to schooling.


Book
Identification of Causal Effects Using Instrumental Variables
Authors: --- --- ---
Year: 1993 Publisher: Cambridge, Mass. National Bureau of Economic Research

Loading...
Export citation

Choose an application

Bookmark

Abstract


Book
Investors' Portfolio Behavior Under Alternative Models of Long-Term Interest Rate Expectations : Unitary, Rational, or Autoregressive
Authors: --- ---
Year: 1980 Publisher: Cambridge, Mass. National Bureau of Economic Research

Loading...
Export citation

Choose an application

Bookmark

Abstract

This paper develops behavioral relationships explaining investors' demands for long-term bonds, using three alternative hypotheses about investors' expectations of future bond prices (yields). The results, based on U.S. 'data for six major categories of bond market investors, consistently support an autoregressive expectations model. The results also have implications for further aspects of investors' portfolio behavior, including expectations formation, response to inflation, and speed of adjustment.


Book
The Distribution of the Instrumental Variables Estimator and Its t-Ratio When the Instrument is a Poor One
Authors: --- ---
Year: 1988 Publisher: Cambridge, Mass. National Bureau of Economic Research

Loading...
Export citation

Choose an application

Bookmark

Abstract

When the instrumental variable is a poor one, in the sense of being weakly correlated with the variable it proxies, the small sample distribution of the IV estimator is concentrated around a value that is inversely related to the feedback in the system and which is often further from the true value than is the plim of OLS. The sample variance of residuals similarly becomes concentrated around a value which reflects feedback and not the variance of the disturbance. The distribution of the t-ratio reflects both of these effects, stronger feedback producing larger t-ratios. Thus, in situations where OLS is badly biased, a poor instrument will lead to spurious inferences under IV estimation with high probability, and generally perform worse than OLS.

Measurement uncertainties in science and technology
Author:
ISBN: 3540209441 Year: 2005 Publisher: Berlin Springer

Loading...
Export citation

Choose an application

Bookmark

Abstract


Book
Local Instrumental Variables
Authors: --- ---
Year: 2000 Publisher: Cambridge, Mass. National Bureau of Economic Research

Loading...
Export citation

Choose an application

Bookmark

Abstract

This paper unites the treatment effect literature and the latent variable literature. The economic questions answered by the commonly used treatment effect parameters are considered. We demonstrate how the marginal treatment effect parameter can be used in a latent variable framework to generate the average treatment effect, the effect of treatment on the treated and the local average treatment effect, thereby establishing a new relationship among these parameters. The method of local instrumental variables directly estimates the marginal treatment effect parameters, and thus can be used to estimate all of the conventional treatment effect parameters when the index condition holds and the parameters are identified. When they are not, the method of local instrumental variables can be used to produce bounds on the parameters with the width of the bounds depending on the width of the support for the index generating the choice of the observed potential outcome.


Book
Numerical analysis for electromagnetic integral equations
Author:
ISBN: 1596933348 9781596933347 9781596933330 159693333X 9781596933347 Year: 2008 Publisher: Boston : Artech House,

Loading...
Export citation

Choose an application

Bookmark

Abstract

Improve EM simulation efforts fast with this applications-focused resource. This unique volume is the first book on integral equation-based methods that combines quantitative formulas for predicting numerical simulation accuracy together with rigorous error estimates and results for dozens of actual electromagnetics and wave propagation problems. You get the latest insights on accuracy-improving methods like regularization and error-increasing effects such as edge singularities and resonance, along with full details on how to determine mesh density, choice of basis functions, and other parameters needed to optimize any numerical simulation. Bridging the gap between abstract academic treatments and the real-world needs of engineers, this timely work introduces various surface integral equation formulations, approaches to discretizing the integral equations, and measures of solution accuracy. It gives you numerical methods for 2D radiation and scattering problems, emphasizing concrete solution error bounds with exactly given constants. Moreover, the book provides techniques for higher order basis functions and 3D problems, focusing on smooth scatterers and edge singularity effects. This informative reference also explores problems involving resonant cavities and structures, and features a comprehensive treatment of resonant scatterers. The final chapter covers the convergence of the fast multipole method with iterative linear system solvers, complete with practical methods for improving the efficiency of iterative solutions.


Book
Demand Analysis of Multiple Goods and Services in Vietnam
Authors: ---
Year: 2021 Publisher: Washington, D.C. : The World Bank,

Loading...
Export citation

Choose an application

Bookmark

Abstract

In 1986 the and#x0189;oi Moi reform changed the economic and social policies in Vietnam, triggering steep economic growth and the shift from a low- to a middle-income economy. In parallel to the economic growth, Vietnam also experienced rapid social and demographic change, which resulted in modified consumption behavior. This paper estimates a Quadratic Almost Ideal Demand System, obtaining income and own- and cross-price elasticities for 10 groups of goods and services that can contribute to the further economic development of Vietnam. To control for potential bias generated by unobserved quality substitution and endogenous unit values, the analysis adopts an instrumental variable method. The results show that household equipment, clothing and accessories, telecommunication, transport, and medical and health services are responsive to income changes, while food, foodstuffs, beverages and tobacco, education, and electricity are income inelastic. Moreover, the analysis detects complementarity between education and the rest of the goods and services, and substitution between health care and household equipment, clothing, and telecommunication services. These results help in understanding recent socioeconomic development patterns in Vietnam and provide updated evidence to support business decisions and economic policy planning.

Listing 1 - 10 of 145 << page
of 15
>>
Sort by