نتایج جستجو برای: imputation

تعداد نتایج: 16711  

2016
Mohamad Saad Alejandro Q. Nato Fiona L. Grimson Steven M. Lewis Lisa A. Brown Elizabeth M. Blue Timothy A. Thornton Elizabeth A. Thompson Ellen M. Wijsman

BACKGROUND In the past few years, imputation approaches have been mainly used in population-based designs of genome-wide association studies, although both family- and population-based imputation methods have been proposed. With the recent surge of family-based designs, family-based imputation has become more important. Imputation methods for both designs are based on identity-by-descent (IBD) ...

2008
Lin Li Hyunshik Lee Annie Lo Greg Norman

In the Pre-Elementary Education Longitudinal Study (PEELS), imputation of item missing data was done using AutoImpute (AI) software, which uses semi-parametric modeling to form imputation classes. In this paper, we summarize PEELS experience with AI, investigate the bias aspect of the imputed data for the PEELS teacher questionnaire data, and study the variance estimation of imputed data using ...

2003
Coen A. Bernaards Melissa M. Farmer Karen Qi Gareth S. Dulai Patricia A. Ganz Katherine L. Kahn

Commonly in survey research, multiple, different analyses are conducted by one or more than one researcher on the same data set. The conclusions from these analyses should be consistent despite the presence of missing data. Multiple imputation is frequently used to ensure consistency of analyses. Two methods for multiple imputation of missing data are a combination of hot deck and regression im...

Journal: :PVLDB 2017
Jose Cambronero John Feser Micah Smith Samuel Madden

Missing values are common in data analysis and present a usability challenge. Users are forced to pick between removing tuples withmissing values or creating a cleaned version of their data by applying a relatively expensive imputation strategy. Our system, ImputeDB, incorporates imputation into a costbased query optimizer, performing necessary imputations onthe-fly for eachquery. This allows u...

2017
Cattram D. Nguyen John B. Carlin Katherine J. Lee

BACKGROUND Multiple imputation has become very popular as a general-purpose method for handling missing data. The validity of multiple-imputation-based analyses relies on the use of an appropriate model to impute the missing values. Despite the widespread use of multiple imputation, there are few guidelines available for checking imputation models. ANALYSIS In this paper, we provide an overvi...

Journal: :IJDWM 2010
Shichao Zhang

In this paper, the author designs an efficient method for imputing iteratively missing target values with semi-parametric kernel regression imputation, known as the semi-parametric iterative imputation algorithm (SIIA). While there is little prior knowledge on the datasets, the proposed iterative imputation method, which impute each missing value several times until the algorithms converges in ...

The objective of this study was to investigate the role of genetic relationships between training and validation set with considering different ratio of phenotypic records of training set on accuracy of genomic prediction via animal models containing genotype × environment interactions in simulated imputation data. For this purpose, four different scenarios using 15k density containing differen...

2017
Ping Xu Tonya M. Smoot Steven McCabe

THE ANALYSIS OF MISSING DATA IN PUBLIC USE SURVEY DATABASES: A SURVEY OF STATISTICAL METHODS Ping Xu November 20, 2004 Missing data is very common in survey research. However, currently few guidelines exist with regard to the diagnosis and remedy to missing data in survey research. The goal of the thesis was to investigate properties and effects of three selected missing data handling technique...

2010
Michael Spratt James Carpenter Jonathan A. C. Sterne John B. Carlin Jon Heron John Henderson Kate Tilling

Multiple imputation is increasingly recommended in epidemiology to adjust for the bias and loss of information that may occur in analyses restricted to study participants with complete data (‘‘complete-case analyses’’). However, little guidance is available on applying the method, including which variables to include in the imputation model and the number of imputations needed. Here, the author...

2016
L. Dee Miller Nate Stender Leen-Kiat Soh Ashok Samal Kevin A. Kupzyk Dee Miller Kevin Kupzyk

Missing values are very common in real-world datasets for a variety of reasons. Deleting data points with missing values can negatively impact the performance of data analysis methods (e.g., machine learning, data mining). Using a human expert to restore the missing values is expensive and time consuming. The alternative is to impute the missing values during data preprocessing using the known ...

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