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- 1. Validation of cognitive functioning categories in the Canadian Community Health Survey -Healthy Aging ArchivedArticles and reports: 82-003-X201000411391Geography: CanadaDescription:
This analysis uses data from the Cognition Module of the 2009 Canadian Community Health Survey - Healthy Aging to validate a categorization of levels of cognitive functioning in the household population aged 45 or older.
Release date: 2010-12-15 - 2. Validation of qualitative methodology applied to a multidimensional instrument with an open question ArchivedArticles and reports: 11-522-X200600110443Description:
The Brazilian population has experienced an ageing process, thus characterizing an increase in the number of elderly people. Instruments have been developed in order to measure the quality of life of elderly individuals. Hence, a questionnaire consisting of various validated instruments and an open question was applied to a group of elderly citizens in the city of Botucatu, SP, Brazil. The analysis of the open question, assessed by qualitative methods, generated eleven categories concerning the elderly people's opinions as regards quality of life and a cluster analysis of such answers was carried out, producing three groups of elderly individuals. Therefore, this work aimed at validating the categories obtained by the open question with the closed questions of the instrument by means of associations and application of chi-square tests at a level of significance of 5%. It was observed that qualitative analysis identifies phenomena regardless of category saturation. The quantitative method, on the other hand, shows the power of each category in a set, that is, as a whole.
Release date: 2008-03-17 - Articles and reports: 11-522-X20020016714Description:
In this highly technical paper, we illustrate the application of the delete-a-group jack-knife variance estimator approach to a particular complex multi-wave longitudinal study, demonstrating its utility for linear regression and other analytic models. The delete-a-group jack-knife variance estimator is proving a very useful tool for measuring variances under complex sampling designs. This technique divides the first-phase sample into mutually exclusive and nearly equal variance groups, deletes one group at a time to create a set of replicates and makes analogous weighting adjustments in each replicate to those done for the sample as a whole. Variance estimation proceeds in the standard (unstratified) jack-knife fashion.
Our application is to the Chicago Health and Aging Project (CHAP), a community-based longitudinal study examining risk factors for chronic health problems of older adults. A major aim of the study is the investigation of risk factors for incident Alzheimer's disease. The current design of CHAP has two components: (1) Every three years, all surviving members of the cohort are interviewed on a variety of health-related topics. These interviews include cognitive and physical function measures. (2) At each of these waves of data collection, a stratified Poisson sample is drawn from among the respondents to the full population interview for detailed clinical evaluation and neuropsychological testing. To investigate risk factors for incident disease, a 'disease-free' cohort is identified at the preceding time point and forms one major stratum in the sampling frame.
We provide proofs of the theoretical applicability of the delete-a-group jack-knife for particular estimators under this Poisson design, paying needed attention to the distinction between finite-population and infinite-population (model) inference. In addition, we examine the issue of determining the 'right number' of variance groups.
Release date: 2004-09-13 - 4. Modeling the burden of cancer in Canada ArchivedArticles and reports: 82-005-X20020016479Geography: CanadaDescription:
The Population Health Model (POHEM) is a policy analysis tool that helps answer "what-if" questions about the health and economic burden of specific diseases and the cost-effectiveness of administering new diagnostic and therapeutic interventions. This simulation model is particularly pertinent in an era of fiscal restraint, when new therapies are generally expensive and difficult policy decisions are being made. More important, it provides a base for a broader framework to inform policy decisions using comprehensive disease data and risk factors. Our "base case" models comprehensively estimate the lifetime costs of treating breast, lung and colorectal cancer in Canada. Our cancer models have shown the large financial burden of diagnostic work-up and initial therapy, as well as the high costs of hospitalizing those dying of cancer. Our core cancer models (lung, breast and colorectal cancer) have been used to evaluate the impact of new practice patterns. We have used these models to evaluate new chemotherapy regimens as therapeutic options for advanced lung cancer; the health and financial impact of reducing the hospital length of stay for initial breast cancer surgery; and the potential impact of population-based screening for colorectal cancer. To date, the most interesting intervention we have studied has been the use of tamoxifen to prevent breast cancer among high risk women.
Release date: 2002-10-08
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- 1. Validation of cognitive functioning categories in the Canadian Community Health Survey -Healthy Aging ArchivedArticles and reports: 82-003-X201000411391Geography: CanadaDescription:
This analysis uses data from the Cognition Module of the 2009 Canadian Community Health Survey - Healthy Aging to validate a categorization of levels of cognitive functioning in the household population aged 45 or older.
Release date: 2010-12-15 - 2. Validation of qualitative methodology applied to a multidimensional instrument with an open question ArchivedArticles and reports: 11-522-X200600110443Description:
The Brazilian population has experienced an ageing process, thus characterizing an increase in the number of elderly people. Instruments have been developed in order to measure the quality of life of elderly individuals. Hence, a questionnaire consisting of various validated instruments and an open question was applied to a group of elderly citizens in the city of Botucatu, SP, Brazil. The analysis of the open question, assessed by qualitative methods, generated eleven categories concerning the elderly people's opinions as regards quality of life and a cluster analysis of such answers was carried out, producing three groups of elderly individuals. Therefore, this work aimed at validating the categories obtained by the open question with the closed questions of the instrument by means of associations and application of chi-square tests at a level of significance of 5%. It was observed that qualitative analysis identifies phenomena regardless of category saturation. The quantitative method, on the other hand, shows the power of each category in a set, that is, as a whole.
Release date: 2008-03-17 - Articles and reports: 11-522-X20020016714Description:
In this highly technical paper, we illustrate the application of the delete-a-group jack-knife variance estimator approach to a particular complex multi-wave longitudinal study, demonstrating its utility for linear regression and other analytic models. The delete-a-group jack-knife variance estimator is proving a very useful tool for measuring variances under complex sampling designs. This technique divides the first-phase sample into mutually exclusive and nearly equal variance groups, deletes one group at a time to create a set of replicates and makes analogous weighting adjustments in each replicate to those done for the sample as a whole. Variance estimation proceeds in the standard (unstratified) jack-knife fashion.
Our application is to the Chicago Health and Aging Project (CHAP), a community-based longitudinal study examining risk factors for chronic health problems of older adults. A major aim of the study is the investigation of risk factors for incident Alzheimer's disease. The current design of CHAP has two components: (1) Every three years, all surviving members of the cohort are interviewed on a variety of health-related topics. These interviews include cognitive and physical function measures. (2) At each of these waves of data collection, a stratified Poisson sample is drawn from among the respondents to the full population interview for detailed clinical evaluation and neuropsychological testing. To investigate risk factors for incident disease, a 'disease-free' cohort is identified at the preceding time point and forms one major stratum in the sampling frame.
We provide proofs of the theoretical applicability of the delete-a-group jack-knife for particular estimators under this Poisson design, paying needed attention to the distinction between finite-population and infinite-population (model) inference. In addition, we examine the issue of determining the 'right number' of variance groups.
Release date: 2004-09-13 - 4. Modeling the burden of cancer in Canada ArchivedArticles and reports: 82-005-X20020016479Geography: CanadaDescription:
The Population Health Model (POHEM) is a policy analysis tool that helps answer "what-if" questions about the health and economic burden of specific diseases and the cost-effectiveness of administering new diagnostic and therapeutic interventions. This simulation model is particularly pertinent in an era of fiscal restraint, when new therapies are generally expensive and difficult policy decisions are being made. More important, it provides a base for a broader framework to inform policy decisions using comprehensive disease data and risk factors. Our "base case" models comprehensively estimate the lifetime costs of treating breast, lung and colorectal cancer in Canada. Our cancer models have shown the large financial burden of diagnostic work-up and initial therapy, as well as the high costs of hospitalizing those dying of cancer. Our core cancer models (lung, breast and colorectal cancer) have been used to evaluate the impact of new practice patterns. We have used these models to evaluate new chemotherapy regimens as therapeutic options for advanced lung cancer; the health and financial impact of reducing the hospital length of stay for initial breast cancer surgery; and the potential impact of population-based screening for colorectal cancer. To date, the most interesting intervention we have studied has been the use of tamoxifen to prevent breast cancer among high risk women.
Release date: 2002-10-08
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