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- Articles and reports: 12-001-X200900211038Description:
We examine overcoming the overestimation in using generalized weight share method (GWSM) caused by link nonresponse in indirect sampling. A few adjustment methods incorporating link nonresponse in using GWSM have been constructed for situations both with and without the availability of auxiliary variables. A simulation study on a longitudinal survey is presented using some of the adjustment methods we recommend. The simulation results show that these adjusted GWSMs perform well in reducing both estimation bias and variance. The advancement in bias reduction is significant.
Release date: 2009-12-23 - 2. International surveys: Motives and methodologies ArchivedArticles and reports: 11-522-X200800010937Description:
The context of the discussion is the increasing incidence of international surveys, of which one is the International Tobacco Control (ITC) Policy Evaluation Project, which began in 2002. The ITC country surveys are longitudinal, and their aim is to evaluate the effects of policy measures being introduced in various countries under the WHO Framework Convention on Tobacco Control. The challenges of organization, data collection and analysis in international surveys are reviewed and illustrated. Analysis is an increasingly important part of the motivation for large scale cross-cultural surveys. The fundamental challenge for analysis is to discern the real response (or lack of response) to policy change, separating it from the effects of data collection mode, differential non-response, external events, time-in-sample, culture, and language. Two problems relevant to statistical analysis are discussed. The first problem is the question of when and how to analyze pooled data from several countries, in order to strengthen conclusions which might be generally valid. While in some cases this seems to be straightforward, there are differing opinions on the extent to which pooling is possible and reasonable. It is suggested that for formal comparisons, random effects models are of conceptual use. The second problem is to find models of measurement across cultures and data collection modes which will enable calibration of continuous, binary and ordinal responses, and produce comparisons from which extraneous effects have been removed. It is noted that hierarchical models provide a natural way of relaxing requirements of model invariance across groups.
Release date: 2009-12-03 - Articles and reports: 11-522-X200800010948Description:
Past survey instruments, whether in the form of a paper questionnaire or telephone script, were their own documentation. Based on this, the ESRC Question Bank was created, providing free-access internet publication of questionnaires, enabling researchers to re-use questions, saving them trouble, whilst improving the comparability of their data with that collected by others. Today however, as survey technology and computer programs have become more sophisticated, accurate comprehension of the latest questionnaires seems more difficult, particularly when each survey team uses its own conventions to document complex items in technical reports. This paper seeks to illustrate these problems and suggest preliminary standards of presentation to be used until the process can be automated.
Release date: 2009-12-03 - 4. Evaluation and treatment of non-response in the ELFE cohort: Results of the pilot studies ArchivedArticles and reports: 11-522-X200800010960Description:
Non-response is inevitable in any survey, despite all the effort put into reducing it at the various stages of the survey. In particular, non-response can cause bias in the estimates. In addition, non-response is an especially serious problem in longitudinal studies because the sample shrinks over time. France's ELFE (Étude Longitudinale Française depuis l'Enfance) is a project that aims to track 20,000 children from birth to adulthood using a multidisciplinary approach. This paper is based on the results of the initial pilot studies conducted in 2007 to test the survey's feasibility and acceptance. The participation rates are presented (response rate, non-response factors) along with a preliminary description of the non-response treatment methods being considered.
Release date: 2009-12-03 - Articles and reports: 11-522-X200800010962Description:
The ÉLDEQ initiated a special data gathering project in March 2008 with the collection of biological materials from 1,973 families. During a typical visit, a nurse collects a blood or saliva sample from the selected child, makes a series of measurements (anthropometry, pulse rate and blood pressure) and administers questionnaires. Planned and supervised by the Institut de la Statistique du Québec (ISQ) and the Université de Montréal, the study is being conducted in cooperation with two private firms and a number of hospitals. This article examines the choice of collection methods, the division of effort among the various players, the sequence of communications and contacts with respondents, the tracing of families who are not contacted, and follow-up on the biological samples. Preliminary field results are also presented.
Release date: 2009-12-03 - Articles and reports: 11-522-X200800010963Description:
BackgroundThere has been a reluctance to conduct child related research studies with, rather than on children in the African continent. Several studies have embarked on this method, however, ethical and privacy challenges still prevail. The Amajuba Child Health and Wellbeing Research Project is a longitudinal study that was conducted with 725 children aged between 9 and 15 years old in KwaZulu Natal in South Africa and also faced the same challenges.
MethodsFocus group discussions and self administered questionnaires were used as data collection techniques for ACHWRP. One of ACHWRP's objectives is to document the consequences of parental or caregiver death on health and well-being of orphans in Amajuba District of KwaZulu Natal. Ethical clearance was received from two ethical review boards.
Lessons learnedEthical challenges included problems of coercion for participation, gatekeeper's and partner's roles, getting consent and assent, recruitment and referral system.Privacy challenges included data collection techniques, curiosity and destruction by members of the family during an interview, the setting where interviews are conducted, logistical issues and the method of recruitment's potential to compromise confidentiality.Resolutions: Detailed consent and assent forms with all relevant information are necessary. Careful selection of partnerships is crucial. Use of a venue that is far from the community is necessary, but in the process making sure that the participants are covered with regards to the expenses of travelling to the venue.
ConclusionConducting research with children entails investing more time and attention to the planning stage of the study.
Release date: 2009-12-03 - Articles and reports: 11-522-X200800010991Description:
In the evaluation of prospective survey designs, statistical agencies generally must consider a large number of design factors that may have a substantial impact on both survey costs and data quality. Assessments of trade-offs between cost and quality are often complicated by limitations on the amount of information available regarding fixed and marginal costs related to: instrument redesign and field testing; the number of primary sample units and sample elements included in the sample; assignment of instrument sections and collection modes to specific sample elements; and (for longitudinal surveys) the number and periodicity of interviews. Similarly, designers often have limited information on the impact of these design factors on data quality.
This paper extends standard design-optimization approaches to account for uncertainty in the abovementioned components of cost and quality. Special attention is directed toward the level of precision required for cost and quality information to provide useful input into the design process; sensitivity of cost-quality trade-offs to changes in assumptions regarding functional forms; and implications for preliminary work focused on collection of cost and quality information. In addition, the paper considers distinctions between cost and quality components encountered in field testing and production work, respectively; incorporation of production-level cost and quality information into adaptive design work; as well as costs and operational risks arising from the collection of detailed cost and quality data during production work. The proposed methods are motivated by, and applied to, work with partitioned redesign of the interview and diary components of the U.S. Consumer Expenditure Survey.
Release date: 2009-12-03 - Articles and reports: 11-522-X200800011000Description:
The present report reviews the results of a mailing experiment that took place within a large scale demonstration project. A postcard and stickers were sent to a random group of project participants in the period between a contact call and a survey. The researchers hypothesized that, because of the additional mailing (the treatment), the response rates to the upcoming survey would increase. There was, however, no difference between the response rates of the treatment group that received the additional mailing and the control group. In the specific circumstances of the mailing experiment, sending project participants a postcard and stickers as a reminder of the upcoming survey and of their participation in the pilot project was not an efficient way to increase response rates.
Release date: 2009-12-03 - Articles and reports: 12-002-X200900110692Description:
Researchers are able to examine changes in trends over time, through the examination of responses to repeatedly-asked questions, among the same respondents, over several cycles of longitudinal data. Working with these repeatedly-measured responses can often be challenging. This article examines trends in youth's volunteering activities, using data from the National Longitudinal Survey of Children and Youth, to highlight several issues that researchers should consider when working with repeated measures.
Release date: 2009-04-22
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- Articles and reports: 12-001-X200900211038Description:
We examine overcoming the overestimation in using generalized weight share method (GWSM) caused by link nonresponse in indirect sampling. A few adjustment methods incorporating link nonresponse in using GWSM have been constructed for situations both with and without the availability of auxiliary variables. A simulation study on a longitudinal survey is presented using some of the adjustment methods we recommend. The simulation results show that these adjusted GWSMs perform well in reducing both estimation bias and variance. The advancement in bias reduction is significant.
Release date: 2009-12-23 - 2. International surveys: Motives and methodologies ArchivedArticles and reports: 11-522-X200800010937Description:
The context of the discussion is the increasing incidence of international surveys, of which one is the International Tobacco Control (ITC) Policy Evaluation Project, which began in 2002. The ITC country surveys are longitudinal, and their aim is to evaluate the effects of policy measures being introduced in various countries under the WHO Framework Convention on Tobacco Control. The challenges of organization, data collection and analysis in international surveys are reviewed and illustrated. Analysis is an increasingly important part of the motivation for large scale cross-cultural surveys. The fundamental challenge for analysis is to discern the real response (or lack of response) to policy change, separating it from the effects of data collection mode, differential non-response, external events, time-in-sample, culture, and language. Two problems relevant to statistical analysis are discussed. The first problem is the question of when and how to analyze pooled data from several countries, in order to strengthen conclusions which might be generally valid. While in some cases this seems to be straightforward, there are differing opinions on the extent to which pooling is possible and reasonable. It is suggested that for formal comparisons, random effects models are of conceptual use. The second problem is to find models of measurement across cultures and data collection modes which will enable calibration of continuous, binary and ordinal responses, and produce comparisons from which extraneous effects have been removed. It is noted that hierarchical models provide a natural way of relaxing requirements of model invariance across groups.
Release date: 2009-12-03 - Articles and reports: 11-522-X200800010948Description:
Past survey instruments, whether in the form of a paper questionnaire or telephone script, were their own documentation. Based on this, the ESRC Question Bank was created, providing free-access internet publication of questionnaires, enabling researchers to re-use questions, saving them trouble, whilst improving the comparability of their data with that collected by others. Today however, as survey technology and computer programs have become more sophisticated, accurate comprehension of the latest questionnaires seems more difficult, particularly when each survey team uses its own conventions to document complex items in technical reports. This paper seeks to illustrate these problems and suggest preliminary standards of presentation to be used until the process can be automated.
Release date: 2009-12-03 - 4. Evaluation and treatment of non-response in the ELFE cohort: Results of the pilot studies ArchivedArticles and reports: 11-522-X200800010960Description:
Non-response is inevitable in any survey, despite all the effort put into reducing it at the various stages of the survey. In particular, non-response can cause bias in the estimates. In addition, non-response is an especially serious problem in longitudinal studies because the sample shrinks over time. France's ELFE (Étude Longitudinale Française depuis l'Enfance) is a project that aims to track 20,000 children from birth to adulthood using a multidisciplinary approach. This paper is based on the results of the initial pilot studies conducted in 2007 to test the survey's feasibility and acceptance. The participation rates are presented (response rate, non-response factors) along with a preliminary description of the non-response treatment methods being considered.
Release date: 2009-12-03 - Articles and reports: 11-522-X200800010962Description:
The ÉLDEQ initiated a special data gathering project in March 2008 with the collection of biological materials from 1,973 families. During a typical visit, a nurse collects a blood or saliva sample from the selected child, makes a series of measurements (anthropometry, pulse rate and blood pressure) and administers questionnaires. Planned and supervised by the Institut de la Statistique du Québec (ISQ) and the Université de Montréal, the study is being conducted in cooperation with two private firms and a number of hospitals. This article examines the choice of collection methods, the division of effort among the various players, the sequence of communications and contacts with respondents, the tracing of families who are not contacted, and follow-up on the biological samples. Preliminary field results are also presented.
Release date: 2009-12-03 - Articles and reports: 11-522-X200800010963Description:
BackgroundThere has been a reluctance to conduct child related research studies with, rather than on children in the African continent. Several studies have embarked on this method, however, ethical and privacy challenges still prevail. The Amajuba Child Health and Wellbeing Research Project is a longitudinal study that was conducted with 725 children aged between 9 and 15 years old in KwaZulu Natal in South Africa and also faced the same challenges.
MethodsFocus group discussions and self administered questionnaires were used as data collection techniques for ACHWRP. One of ACHWRP's objectives is to document the consequences of parental or caregiver death on health and well-being of orphans in Amajuba District of KwaZulu Natal. Ethical clearance was received from two ethical review boards.
Lessons learnedEthical challenges included problems of coercion for participation, gatekeeper's and partner's roles, getting consent and assent, recruitment and referral system.Privacy challenges included data collection techniques, curiosity and destruction by members of the family during an interview, the setting where interviews are conducted, logistical issues and the method of recruitment's potential to compromise confidentiality.Resolutions: Detailed consent and assent forms with all relevant information are necessary. Careful selection of partnerships is crucial. Use of a venue that is far from the community is necessary, but in the process making sure that the participants are covered with regards to the expenses of travelling to the venue.
ConclusionConducting research with children entails investing more time and attention to the planning stage of the study.
Release date: 2009-12-03 - Articles and reports: 11-522-X200800010991Description:
In the evaluation of prospective survey designs, statistical agencies generally must consider a large number of design factors that may have a substantial impact on both survey costs and data quality. Assessments of trade-offs between cost and quality are often complicated by limitations on the amount of information available regarding fixed and marginal costs related to: instrument redesign and field testing; the number of primary sample units and sample elements included in the sample; assignment of instrument sections and collection modes to specific sample elements; and (for longitudinal surveys) the number and periodicity of interviews. Similarly, designers often have limited information on the impact of these design factors on data quality.
This paper extends standard design-optimization approaches to account for uncertainty in the abovementioned components of cost and quality. Special attention is directed toward the level of precision required for cost and quality information to provide useful input into the design process; sensitivity of cost-quality trade-offs to changes in assumptions regarding functional forms; and implications for preliminary work focused on collection of cost and quality information. In addition, the paper considers distinctions between cost and quality components encountered in field testing and production work, respectively; incorporation of production-level cost and quality information into adaptive design work; as well as costs and operational risks arising from the collection of detailed cost and quality data during production work. The proposed methods are motivated by, and applied to, work with partitioned redesign of the interview and diary components of the U.S. Consumer Expenditure Survey.
Release date: 2009-12-03 - Articles and reports: 11-522-X200800011000Description:
The present report reviews the results of a mailing experiment that took place within a large scale demonstration project. A postcard and stickers were sent to a random group of project participants in the period between a contact call and a survey. The researchers hypothesized that, because of the additional mailing (the treatment), the response rates to the upcoming survey would increase. There was, however, no difference between the response rates of the treatment group that received the additional mailing and the control group. In the specific circumstances of the mailing experiment, sending project participants a postcard and stickers as a reminder of the upcoming survey and of their participation in the pilot project was not an efficient way to increase response rates.
Release date: 2009-12-03 - Articles and reports: 12-002-X200900110692Description:
Researchers are able to examine changes in trends over time, through the examination of responses to repeatedly-asked questions, among the same respondents, over several cycles of longitudinal data. Working with these repeatedly-measured responses can often be challenging. This article examines trends in youth's volunteering activities, using data from the National Longitudinal Survey of Children and Youth, to highlight several issues that researchers should consider when working with repeated measures.
Release date: 2009-04-22
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