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- Articles and reports: 12-001-X20060029550Description:
In this paper, the geometric, optimization-based, and Lavallée and Hidiroglou (LH) approaches to stratification are compared. The geometric stratification method is an approximation, whereas the other two approaches, which employ numerical methods to perform stratification, may be seen as optimal stratification methods. The algorithm of the geometric stratification is very simple compared to the two other approaches, but it does not take into account the construction of a take-all stratum, which is usually constructed when a positively skewed population is stratified. In the optimization-based stratification, one may consider any form of optimization function and its constraints. In a comparative numerical study based on five positively skewed artificial populations, the optimization approach was more efficient in each of the cases studied compared to the geometric stratification. In addition, the geometric and optimization approaches are compared with the LH algorithm. In this comparison, the geometric stratification approach was found to be less efficient than the LH algorithm, whereas efficiency of the optimization approach was similar to the efficiency of the LH algorithm. Nevertheless, strata boundaries evaluated via the geometric stratification may be seen as efficient starting points for the optimization approach.
Release date: 2006-12-21 - 2. Are Internet users tuning out traditional media? ArchivedArticles and reports: 88-003-X20060039533Geography: CanadaDescription:
Over the past decade, Internet content has evolved to the point where it now represents a significant source of information and entertainment for many people. The Internet has changed the way that many individuals and organizations gather information, and has undoubtedly had some influence on their use of traditional media. While few Canadians had Internet access and went online to gather news information in the mid-1990's, today many use the Internet to access online newspapers, reports, discussion forums and even blogs. In 2005 for example, about 62% of home Internet users - or 38% of Canadian adults overall - went online to view news or sports information (Statistics Canada 2006).
Release date: 2006-12-06 - Articles and reports: 56F0004M2006013Geography: CanadaDescription:
This study aims to develop a better understanding of the social impacts associated with Internet use in Canada. Although much work has been accomplished on the penetration and use of the Internet, this study uses data from the General Social Survey, Cycle 19: Time Use to better understand how personal use of the Internet fits in the day-to-day lives of Canadians.
The survey provides a time-diary account of respondent activities over a 24-hour period, enabling detailed comparisons among heavy Internet users, moderate users, and non-Internet users and their time allocation decisions. Heavy Internet users spent more time alone during the diary day than non-Internet users, even when compared to people of the same social and demographic background. Although they spent less time with family and friends, many heavy Internet users participated in online activities involving social interaction, such as email or chatting with others.
Release date: 2006-08-02 - Articles and reports: 81-595-M2006041Geography: CanadaDescription:
Through research and consultation, Statistics Canada was asked to investigate the availability of data to measure the infrastructure of health programs in educational institutions and the flow of individuals through these programs and into health occupations.
This document marks the first stage in this project. Based upon nation-wide consultations, it lays out a conceptual framework and outlines a set of questions about health education, the individuals pursuing health education, the flow of individuals through health education, and the factors which affect that flow. The outline will enable the identification of information that is needed to support efficient and effective decisions and policies about health education programs and health human resources management.
Release date: 2006-04-24 - 5. Factors Affecting Biotechnology Innovation in Canada: Analysis of the 2001 Biotechnology Use and Development ArchivedArticles and reports: 21-601-M2006078Description:
This study explores factors which determine innovative activity within the Canadian biotechnology industry.
Release date: 2006-03-30 - Articles and reports: 88-003-X20060019098Geography: CanadaDescription:
This article examines age and how relates to patterns of computer and Internet use. While age is often connected with the likelihood that someone will own or have access to computers and the Internet, age also bears strong relationships to behavior and participation in online activities, much as it does with activities in life in general.
Release date: 2006-02-27 - Articles and reports: 12-001-X20050029044Description:
Complete data methods for estimating the variances of survey estimates are biased when some data are imputed. This paper uses simulation to compare the performance of the model-assisted, the adjusted jackknife, and the multiple imputation methods for estimating the variance of a total when missing items have been imputed using hot deck imputation. The simulation studies the properties of the variance estimates for imputed estimates of totals for the full population and for domains from a single-stage disproportionate stratified sample design when underlying assumptions, such as unbiasedness of the point estimate and item responses being randomly missing within hot deck cells, do not hold. The variance estimators for full population estimates produce confidence intervals with coverage rates near the nominal level even under modest departures from the assumptions, but this finding does not apply for the domain estimates. Coverage is most sensitive to bias in the point estimates. As the simulation demonstrates, even if an imputation method gives almost unbiased estimates for the full population, estimates for domains may be very biased.
Release date: 2006-02-17 - Articles and reports: 12-001-X20050029046Description:
Nonresponse weighting is a common method for handling unit nonresponse in surveys. The method is aimed at reducing nonresponse bias, and it is often accompanied by an increase in variance. Hence, the efficacy of weighting adjustments is often seen as a bias-variance trade-off. This view is an oversimplification, nonresponse weighting can in fact lead to a reduction in variance as well as bias. A covariate for a weighting adjustment must have two characteristics to reduce nonresponse bias: it needs to be related to the probability of response, and it needs to be related to the survey outcome. If the latter is true, then weighting can reduce, not increase, sampling variance. A detailed analysis of bias and variance is provided in the setting of weighting for an estimate of a survey mean based on adjustment cells. The analysis suggests that the most important feature of variables for inclusion in weighting adjustments is that they are predictive of survey outcomes; prediction of the propensity to respond is a secondary, though useful, goal. Empirical estimates of root mean squared error for assessing when weighting is effective are proposed and evaluated in a simulation study. A simple composite estimator based on the empirical root mean squared error yields some gains over the weighted estimator in the simulations.
Release date: 2006-02-17
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Articles and reports (8)
Articles and reports (8) ((8 results))
- Articles and reports: 12-001-X20060029550Description:
In this paper, the geometric, optimization-based, and Lavallée and Hidiroglou (LH) approaches to stratification are compared. The geometric stratification method is an approximation, whereas the other two approaches, which employ numerical methods to perform stratification, may be seen as optimal stratification methods. The algorithm of the geometric stratification is very simple compared to the two other approaches, but it does not take into account the construction of a take-all stratum, which is usually constructed when a positively skewed population is stratified. In the optimization-based stratification, one may consider any form of optimization function and its constraints. In a comparative numerical study based on five positively skewed artificial populations, the optimization approach was more efficient in each of the cases studied compared to the geometric stratification. In addition, the geometric and optimization approaches are compared with the LH algorithm. In this comparison, the geometric stratification approach was found to be less efficient than the LH algorithm, whereas efficiency of the optimization approach was similar to the efficiency of the LH algorithm. Nevertheless, strata boundaries evaluated via the geometric stratification may be seen as efficient starting points for the optimization approach.
Release date: 2006-12-21 - 2. Are Internet users tuning out traditional media? ArchivedArticles and reports: 88-003-X20060039533Geography: CanadaDescription:
Over the past decade, Internet content has evolved to the point where it now represents a significant source of information and entertainment for many people. The Internet has changed the way that many individuals and organizations gather information, and has undoubtedly had some influence on their use of traditional media. While few Canadians had Internet access and went online to gather news information in the mid-1990's, today many use the Internet to access online newspapers, reports, discussion forums and even blogs. In 2005 for example, about 62% of home Internet users - or 38% of Canadian adults overall - went online to view news or sports information (Statistics Canada 2006).
Release date: 2006-12-06 - Articles and reports: 56F0004M2006013Geography: CanadaDescription:
This study aims to develop a better understanding of the social impacts associated with Internet use in Canada. Although much work has been accomplished on the penetration and use of the Internet, this study uses data from the General Social Survey, Cycle 19: Time Use to better understand how personal use of the Internet fits in the day-to-day lives of Canadians.
The survey provides a time-diary account of respondent activities over a 24-hour period, enabling detailed comparisons among heavy Internet users, moderate users, and non-Internet users and their time allocation decisions. Heavy Internet users spent more time alone during the diary day than non-Internet users, even when compared to people of the same social and demographic background. Although they spent less time with family and friends, many heavy Internet users participated in online activities involving social interaction, such as email or chatting with others.
Release date: 2006-08-02 - Articles and reports: 81-595-M2006041Geography: CanadaDescription:
Through research and consultation, Statistics Canada was asked to investigate the availability of data to measure the infrastructure of health programs in educational institutions and the flow of individuals through these programs and into health occupations.
This document marks the first stage in this project. Based upon nation-wide consultations, it lays out a conceptual framework and outlines a set of questions about health education, the individuals pursuing health education, the flow of individuals through health education, and the factors which affect that flow. The outline will enable the identification of information that is needed to support efficient and effective decisions and policies about health education programs and health human resources management.
Release date: 2006-04-24 - 5. Factors Affecting Biotechnology Innovation in Canada: Analysis of the 2001 Biotechnology Use and Development ArchivedArticles and reports: 21-601-M2006078Description:
This study explores factors which determine innovative activity within the Canadian biotechnology industry.
Release date: 2006-03-30 - Articles and reports: 88-003-X20060019098Geography: CanadaDescription:
This article examines age and how relates to patterns of computer and Internet use. While age is often connected with the likelihood that someone will own or have access to computers and the Internet, age also bears strong relationships to behavior and participation in online activities, much as it does with activities in life in general.
Release date: 2006-02-27 - Articles and reports: 12-001-X20050029044Description:
Complete data methods for estimating the variances of survey estimates are biased when some data are imputed. This paper uses simulation to compare the performance of the model-assisted, the adjusted jackknife, and the multiple imputation methods for estimating the variance of a total when missing items have been imputed using hot deck imputation. The simulation studies the properties of the variance estimates for imputed estimates of totals for the full population and for domains from a single-stage disproportionate stratified sample design when underlying assumptions, such as unbiasedness of the point estimate and item responses being randomly missing within hot deck cells, do not hold. The variance estimators for full population estimates produce confidence intervals with coverage rates near the nominal level even under modest departures from the assumptions, but this finding does not apply for the domain estimates. Coverage is most sensitive to bias in the point estimates. As the simulation demonstrates, even if an imputation method gives almost unbiased estimates for the full population, estimates for domains may be very biased.
Release date: 2006-02-17 - Articles and reports: 12-001-X20050029046Description:
Nonresponse weighting is a common method for handling unit nonresponse in surveys. The method is aimed at reducing nonresponse bias, and it is often accompanied by an increase in variance. Hence, the efficacy of weighting adjustments is often seen as a bias-variance trade-off. This view is an oversimplification, nonresponse weighting can in fact lead to a reduction in variance as well as bias. A covariate for a weighting adjustment must have two characteristics to reduce nonresponse bias: it needs to be related to the probability of response, and it needs to be related to the survey outcome. If the latter is true, then weighting can reduce, not increase, sampling variance. A detailed analysis of bias and variance is provided in the setting of weighting for an estimate of a survey mean based on adjustment cells. The analysis suggests that the most important feature of variables for inclusion in weighting adjustments is that they are predictive of survey outcomes; prediction of the propensity to respond is a secondary, though useful, goal. Empirical estimates of root mean squared error for assessing when weighting is effective are proposed and evaluated in a simulation study. A simple composite estimator based on the empirical root mean squared error yields some gains over the weighted estimator in the simulations.
Release date: 2006-02-17
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