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All (8) ((8 results))

  • Articles and reports: 12-001-X202100200006
    Description:

    Sample-based calibration occurs when the weights of a survey are calibrated to control totals that are random, instead of representing fixed population-level totals. Control totals may be estimated from different phases of the same survey or from another survey. Under sample-based calibration, valid variance estimation requires that the error contribution due to estimating the control totals be accounted for. We propose a new variance estimation method that directly uses the replicate weights from two surveys, one survey being used to provide control totals for calibration of the other survey weights. No restrictions are set on the nature of the two replication methods and no variance-covariance estimates need to be computed, making the proposed method straightforward to implement in practice. A general description of the method for surveys with two arbitrary replication methods with different numbers of replicates is provided. It is shown that the resulting variance estimator is consistent for the asymptotic variance of the calibrated estimator, when calibration is done using regression estimation or raking. The method is illustrated in a real-world application, in which the demographic composition of two surveys needs to be harmonized to improve the comparability of the survey estimates.

    Release date: 2022-01-06

  • Articles and reports: 12-001-X202000200002
    Description:

    In many large-scale surveys, estimates are produced for numerous small domains defined by cross-classifications of demographic, geographic and other variables. Even though the overall sample size of such surveys might be very large, samples sizes for domains are sometimes too small for reliable estimation. We propose an improved estimation approach that is applicable when “natural” or qualitative relationships (such as orderings or other inequality constraints) can be formulated for the domain means at the population level. We stay within a design-based inferential framework but impose constraints representing these relationships on the sample-based estimates. The resulting constrained domain estimator is shown to be design consistent and asymptotically normally distributed as long as the constraints are asymptotically satisfied at the population level. The estimator and its associated variance estimator are readily implemented in practice. The applicability of the method is illustrated on data from the 2015 U.S. National Survey of College Graduates.

    Release date: 2020-12-15

  • Articles and reports: 12-001-X201400214118
    Description:

    Bagging is a powerful computational method used to improve the performance of inefficient estimators. This article is a first exploration of the use of bagging in survey estimation, and we investigate the effects of bagging on non-differentiable survey estimators including sample distribution functions and quantiles, among others. The theoretical properties of bagged survey estimators are investigated under both design-based and model-based regimes. In particular, we show the design consistency of the bagged estimators, and obtain the asymptotic normality of the estimators in the model-based context. The article describes how implementation of bagging for survey estimators can take advantage of replicates developed for survey variance estimation, providing an easy way for practitioners to apply bagging in existing surveys. A major remaining challenge in implementing bagging in the survey context is variance estimation for the bagged estimators themselves, and we explore two possible variance estimation approaches. Simulation experiments reveal the improvement of the proposed bagging estimator relative to the original estimator and compare the two variance estimation approaches.

    Release date: 2014-12-19

  • Articles and reports: 12-001-X201100211610
    Description:

    In this paper, a discussion of the three papers from the US Census Bureau special compilation is presented.

    Release date: 2011-12-21

  • Articles and reports: 12-001-X200900211039
    Description:

    Propensity weighting is a procedure to adjust for unit nonresponse in surveys. A form of implementing this procedure consists of dividing the sampling weights by estimates of the probabilities that the sampled units respond to the survey. Typically, these estimates are obtained by fitting parametric models, such as logistic regression. The resulting adjusted estimators may become biased when the specified parametric models are incorrect. To avoid misspecifying such a model, we consider nonparametric estimation of the response probabilities by local polynomial regression. We study the asymptotic properties of the resulting estimator under quasi-randomization. The practical behavior of the proposed nonresponse adjustment approach is evaluated on NHANES data.

    Release date: 2009-12-23

  • Articles and reports: 11-536-X200900110810
    Description:

    Post-stratification is frequently used to improve the precision of survey estimators when categorical auxiliary information is available from sources outside the survey. In natural resource surveys, such information is often obtained from remote sensing data, classified into categories and displayed as pixel-based maps. These maps may be constructed based on classification models fitted to the sample data. Post-stratification of the sample data based on categories derived from the sample data ("endogenous post-stratification") violates several standard post-stratification assumptions, and has been generally considered invalid as a design-based estimation method. In this presentation, properties of the endogenous post-stratification estimator are derived for the case of a sample-fitted generalized linear model. Design consistency of the endogenous post-stratification estimator is established under mild conditions. Under a superpopulation model, consistency and asymptotic normality of the endogenous post-stratification estimator are established. Simulation experiments demonstrate that the practical effect of first fitting a model to the survey data before post-stratifying is small, even for relatively small sample sizes.

    Release date: 2009-08-11

  • Articles and reports: 12-001-X20070019850
    Description:

    Auxiliary information is often used to improve the precision of survey estimators of finite population means and totals through ratio or linear regression estimation techniques. Resulting estimators have good theoretical and practical properties, including invariance, calibration and design consistency. However, it is not always clear that ratio or linear models are good approximations to the true relationship between the auxiliary variables and the variable of interest in the survey, resulting in efficiency loss when the model is not appropriate. In this article, we explain how regression estimation can be extended to incorporate semiparametric regression models, in both simple and more complicated designs. While maintaining the good theoretical and practical properties of the linear models, semiparametric models are better able to capture complicated relationships between variables. This often results in substantial gains in efficiency. The applicability of the approach for complex designs using multiple types of auxiliary variables will be illustrated by estimating several acidification-related characteristics for a survey of lakes in the Northeastern US.

    Release date: 2007-06-28

  • Articles and reports: 12-001-X20040016993
    Description:

    The weighting cell estimator corrects for unit nonresponse by dividing the sample into homogeneous groups (cells) and applying a ratio correction to the respondents within each cell. Previous studies of the statistical properties of weighting cell estimators have assumed that these cells correspond to known population cells with homogeneous characteristics. In this article, we study the properties of the weighting cell estimator under a response probability model that does not require correct specification of homogeneous population cells. Instead, we assume that the response probabilities are a smooth but otherwise unspecified function of a known auxiliary variable. Under this more general model, we study the robustness of the weighting cell estimator against model misspecification. We show that, even when the population cells are unknown, the estimator is consistent with respect to the sampling design and the response model. We describe the effect of the number of weighting cells on the asymptotic properties of the estimator. Simulation experiments explore the finite sample properties of the estimator. We conclude with some guidance on how to select the size and number of cells for practical implementation of weighting cell estimation when those cells cannot be specified a priori.

    Release date: 2004-07-14
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Articles and reports (8)

Articles and reports (8) ((8 results))

  • Articles and reports: 12-001-X202100200006
    Description:

    Sample-based calibration occurs when the weights of a survey are calibrated to control totals that are random, instead of representing fixed population-level totals. Control totals may be estimated from different phases of the same survey or from another survey. Under sample-based calibration, valid variance estimation requires that the error contribution due to estimating the control totals be accounted for. We propose a new variance estimation method that directly uses the replicate weights from two surveys, one survey being used to provide control totals for calibration of the other survey weights. No restrictions are set on the nature of the two replication methods and no variance-covariance estimates need to be computed, making the proposed method straightforward to implement in practice. A general description of the method for surveys with two arbitrary replication methods with different numbers of replicates is provided. It is shown that the resulting variance estimator is consistent for the asymptotic variance of the calibrated estimator, when calibration is done using regression estimation or raking. The method is illustrated in a real-world application, in which the demographic composition of two surveys needs to be harmonized to improve the comparability of the survey estimates.

    Release date: 2022-01-06

  • Articles and reports: 12-001-X202000200002
    Description:

    In many large-scale surveys, estimates are produced for numerous small domains defined by cross-classifications of demographic, geographic and other variables. Even though the overall sample size of such surveys might be very large, samples sizes for domains are sometimes too small for reliable estimation. We propose an improved estimation approach that is applicable when “natural” or qualitative relationships (such as orderings or other inequality constraints) can be formulated for the domain means at the population level. We stay within a design-based inferential framework but impose constraints representing these relationships on the sample-based estimates. The resulting constrained domain estimator is shown to be design consistent and asymptotically normally distributed as long as the constraints are asymptotically satisfied at the population level. The estimator and its associated variance estimator are readily implemented in practice. The applicability of the method is illustrated on data from the 2015 U.S. National Survey of College Graduates.

    Release date: 2020-12-15

  • Articles and reports: 12-001-X201400214118
    Description:

    Bagging is a powerful computational method used to improve the performance of inefficient estimators. This article is a first exploration of the use of bagging in survey estimation, and we investigate the effects of bagging on non-differentiable survey estimators including sample distribution functions and quantiles, among others. The theoretical properties of bagged survey estimators are investigated under both design-based and model-based regimes. In particular, we show the design consistency of the bagged estimators, and obtain the asymptotic normality of the estimators in the model-based context. The article describes how implementation of bagging for survey estimators can take advantage of replicates developed for survey variance estimation, providing an easy way for practitioners to apply bagging in existing surveys. A major remaining challenge in implementing bagging in the survey context is variance estimation for the bagged estimators themselves, and we explore two possible variance estimation approaches. Simulation experiments reveal the improvement of the proposed bagging estimator relative to the original estimator and compare the two variance estimation approaches.

    Release date: 2014-12-19

  • Articles and reports: 12-001-X201100211610
    Description:

    In this paper, a discussion of the three papers from the US Census Bureau special compilation is presented.

    Release date: 2011-12-21

  • Articles and reports: 12-001-X200900211039
    Description:

    Propensity weighting is a procedure to adjust for unit nonresponse in surveys. A form of implementing this procedure consists of dividing the sampling weights by estimates of the probabilities that the sampled units respond to the survey. Typically, these estimates are obtained by fitting parametric models, such as logistic regression. The resulting adjusted estimators may become biased when the specified parametric models are incorrect. To avoid misspecifying such a model, we consider nonparametric estimation of the response probabilities by local polynomial regression. We study the asymptotic properties of the resulting estimator under quasi-randomization. The practical behavior of the proposed nonresponse adjustment approach is evaluated on NHANES data.

    Release date: 2009-12-23

  • Articles and reports: 11-536-X200900110810
    Description:

    Post-stratification is frequently used to improve the precision of survey estimators when categorical auxiliary information is available from sources outside the survey. In natural resource surveys, such information is often obtained from remote sensing data, classified into categories and displayed as pixel-based maps. These maps may be constructed based on classification models fitted to the sample data. Post-stratification of the sample data based on categories derived from the sample data ("endogenous post-stratification") violates several standard post-stratification assumptions, and has been generally considered invalid as a design-based estimation method. In this presentation, properties of the endogenous post-stratification estimator are derived for the case of a sample-fitted generalized linear model. Design consistency of the endogenous post-stratification estimator is established under mild conditions. Under a superpopulation model, consistency and asymptotic normality of the endogenous post-stratification estimator are established. Simulation experiments demonstrate that the practical effect of first fitting a model to the survey data before post-stratifying is small, even for relatively small sample sizes.

    Release date: 2009-08-11

  • Articles and reports: 12-001-X20070019850
    Description:

    Auxiliary information is often used to improve the precision of survey estimators of finite population means and totals through ratio or linear regression estimation techniques. Resulting estimators have good theoretical and practical properties, including invariance, calibration and design consistency. However, it is not always clear that ratio or linear models are good approximations to the true relationship between the auxiliary variables and the variable of interest in the survey, resulting in efficiency loss when the model is not appropriate. In this article, we explain how regression estimation can be extended to incorporate semiparametric regression models, in both simple and more complicated designs. While maintaining the good theoretical and practical properties of the linear models, semiparametric models are better able to capture complicated relationships between variables. This often results in substantial gains in efficiency. The applicability of the approach for complex designs using multiple types of auxiliary variables will be illustrated by estimating several acidification-related characteristics for a survey of lakes in the Northeastern US.

    Release date: 2007-06-28

  • Articles and reports: 12-001-X20040016993
    Description:

    The weighting cell estimator corrects for unit nonresponse by dividing the sample into homogeneous groups (cells) and applying a ratio correction to the respondents within each cell. Previous studies of the statistical properties of weighting cell estimators have assumed that these cells correspond to known population cells with homogeneous characteristics. In this article, we study the properties of the weighting cell estimator under a response probability model that does not require correct specification of homogeneous population cells. Instead, we assume that the response probabilities are a smooth but otherwise unspecified function of a known auxiliary variable. Under this more general model, we study the robustness of the weighting cell estimator against model misspecification. We show that, even when the population cells are unknown, the estimator is consistent with respect to the sampling design and the response model. We describe the effect of the number of weighting cells on the asymptotic properties of the estimator. Simulation experiments explore the finite sample properties of the estimator. We conclude with some guidance on how to select the size and number of cells for practical implementation of weighting cell estimation when those cells cannot be specified a priori.

    Release date: 2004-07-14
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