The reliability of studies that use Canadian Community Health Survey (CCHS) data from multiple cycles depends on data consistency. Our goal has been to create a tool that highlights variable changes and to evaluate their effects when data is combined across cycles. Using the Derived Variable Specifications, Data Dictionaries and Questionnaires, changes in CCHS components were tracked for selected variables/modules. Currently the document covers cycles 1.1 to 4.1 (years 2001 to 2008).
The Content Tracking Tool (CTT) was developed as a spreadsheet document. The related worksheets provide information on selected CCHS modules and their variables across cycles, including the questions, coding and universe of respondents associated with each variable. Changes that have taken place between cycles are detailed. In addition, colour-coded cautions allow users to quickly identify the variables that are consistent or inconsistent through cycles.
Organization of the tool is detailed in Document Overview.
Frequently Asked Questions
Q1. My research focuses on the province of Ontario. Which optional modules were selected by this province?
A1 The Content worksheet of the Content Tracking Tool (CTT) shows which modules are common, optional, theme or sub-sample content. This worksheet also identifies the provinces that selected each module for Cycles 1.1 through 4.1.
Q2. Are all the variables of the Canadian Community Health Survey included in the CTT?
A2 Most variables were included in the tool. A complete listing of the selected modules can be found in the “Table of Contents” or “Content” sections of the tool. Using the embedded Sort and Filter functions will allow the user to focus on specific modules of interest.
Q3. My research is based on a specific module. How can I see how this module has changed over time?
A3 The “Variable Summary” will first show you all the variables included within your module of interest. Use the Sort and Filter button to select your module of interest. All the associated variables were included with a caution summary that shows whether they are safe to combine across different cycles. In addition, this worksheet shows whether the name of the variables have changed over time. Following this, any changes specific to question wording and coding can be found in the “Questions” and “Coding” worksheets, respectively.
Q4. Have the survey questions regarding Health Disease changed since Cycle 1.1?
A4 Here are tips for your search:
- Start with the “Questions” worksheet. Search the sheet for your key words using the Find function (short code: Ctrl + F).
- Once your key words have been found, locate the associated variable name(s). Read across the row to establish whether changes have occurred across the cycles.
- Search for the same variable name(s) in the “Coding” worksheet to determine whether changes have occurred. Review the caution summaries and analyst notes to determine the safety of combining cycles.
Q5. My variable of interest is labelled as Yellow (use with caution). Will combining this variable across different cycles decrease the reliability of my data?
A5 If you do not check the variable coding and question wording changes the reliability of your data may decrease. However, by reading the analyst notes and reviewing the changes identified in the “Questions” and “Coding” worksheets, you may be able to generate consistency across the cycles.
Q6. Where can I access the survey files?
A6 The Public Use Microdata Files (PUMF) for derived variable specifications, data dictionaries, topical indices, questionnaires and user guides can be found on the Statistics Canada website.
The data files are also available through the Data Liberation Initiative (DLI).
Analysts who intend to use multiple CCHS cycles to either:
- Combine survey cycles to increase the effective sample size. For example, to examine prevalence of diabetes across different ethnic groups.(ref)
- Examine trends across time. For example, to examine changes in rates of health risk behaviours such as smoking, obesity or physical activity.
It is expected that this tool will be of value to a diverse community of data users including federal and provincial departments of health and human resources, health regions, social service agencies, research community, health professionals, non-profit health organizations and students.
- Public Use Microdata Files (PUMF) - Developed from the master files using a technique that balances the need to ensure respondent confidentiality with the need to produce the most useful data possible at the health region level. Variables most likely to lead to identification of an individual are deleted from the data file or are collapsed to broader categories. The PUMF contains the data collected over two years.
- Derived variable - A variable calculated from one or more collected or coded variables, usually calculated during head office processing (e.g., Health Utility Index). To facilitate data analysis and to minimize the risk of error, a number of variables on the file have been derived using items found on the CCHS questionnaire.
- Flag variable - A variable calculated from one or more collected variables (like a derived variable), but usually calculated by the data collection computer application for later use during the interview (e.g., work flag).
- Grouped variable - Collected, coded, suppressed or derived variables collapsed into groups (e.g., age groups)
- Common content - Questionnaire modules asked of all respondents in all health regions. The common content component is divided into three: the annual common content (previously referred to as core content), the one year and two-year common content (previously referred to as theme content). The annual common content consists of questions asked of all survey respondents. The one-year and two-year common content (previously called theme content) comprises questions related to a specific topic. Until 2005, the CCHS data were collected every two years over a one-year period and released every two years.
- Optional content - The optional content component gives health regions the opportunity to select content that addresses their provincial or regional public health priorities. When a module was selected as optional content by a given health region, it was asked of all respondents in the region. The optional content is selected from a long list of modules available for inclusion in the CCHS.
- Sub-sample content - Questionnaire modules which were asked only of a subset of respondents. The aim was to permit calculation of provincial and national estimates while minimising response burden. Variables from sub-sample content modules are designated with a "Z" in position 4 of the variable name; e.g., ACCZ_01.
Limitation of Liability
In no event shall the OHRI and Statistics Canada or its partners, directors, employees, agents, or licensors be liable for damages of any kind arising from the use of information in the Tool.
The tool was developed by the Population Health Improvement Network in collaboration with Statistics Canada. Project team: Trudy O'Bryan (analysts)1, Meltem Tuna1, Doug Manuel1,2 Deirdre Hennessy 1,2 Claudia Sanmartin1,2, Funding was provided by Dr. Manuel's Chair CIHR/PHIRN/PHAC. 1 – Ottawa Hospital Research Institute 2 – Statistics Canada.
Disclaimer of Warranties
Information and content are provided "as is". By using the CTT, the users acknowledge and agree that they will use the CTT at their own risk and liability.
- Statistics Canada. 2001. Canadian Community Health Survey (CCHS) (Cycle 1.1)
- Statistics Canada. 2003. Canadian Community Health Survey (CCHS) (Cycle 2.1)
- Statistics Canada. 2005. Canadian Community Health Survey (CCHS) (Cycle 3.1)
- Statistics Canada. 2007. Canadian Community Health Survey (CCHS) (Cycle 4.1)
- Statistics Canada. 2010. Canadian Community Health Survey (CCHS) Annual Component: User Guide 2010 and 2009-2010
- Statistics Canada. 2001. Canadian Community Health Survey (CCHS) Cycle 1.1 Public Use Micro Data File (PUMF). Derived Variable (DV) Specifications.
- Statistics Canada. 2005. Canadian Community Health Survey (CCHS) Cycle 2.1 Public Use Micro Data File (PUMF). Derived and Grouped Variable Specifications.
- Statistics Canada. 2006. Canadian Community Health Survey (CCHS) Cycle 3.1 (2005). Public Use Micro Data File (PUMF). Integrated Derived Variable (DV) and Grouped Variable Specifications.
- Statistics Canada. 2008. Canadian Community Health Survey (CCHS). 2008 (Annual component) and 2007-2008 Derived Variable (DV) Specifications. Master and share files and Public Use Microdata File (PUMF).
- Statistics Canada. 2002. CCHS Cycle 1.1: Data Dictionary, Public Use Microdata File.
- Statistics Canada. 2005. CCHS Cycle 2.1: Data Dictionary, Public Use Microdata File.
- Statistics Canada. 2006. CCHS Cycle 3.1: Data Dictionary, Public Use Microdata File.
- Statistics Canada. 2009. CCHS 2007-2008: Data Dictionary, Public Use Microdata File.
- Statistics Canada. 2001. Canadian Community Health Survey (CCHS). Questionnaire for Cycle 1.1, September 2000 – November 2001.
- Statistics Canada. 2005. Canadian Community Health Survey (CCHS). Questionnaire for Cycle 2.1, January 2003 to November 2003. Revised version – July 2005.
- Statistics Canada. 2005. Canadian Community Health Survey, Cycle 3.1 June 2005.
- Statistics Canada. 2008. Canadian Community Health Survey (CCHS) 2007 Questionnaire.
- Statistics Canada. 2001. User Guide, CCHS Cycle 1.1 (2000-2001), Public-use Microdata File.
- Statistics Canada. 2003. Canadian Community Health Survey 2003. User Guide for the Public Use Microdata File.
- Statistics Canada. 2006. Canadian Community Health Survey (CCHS), Cycle 3.1 (2005). Public Use Microdata File (PUMF) User Guide.
- Statistics Canada. 2008. Canadian Community Health Survey (CCHS), 2007 Microdata Files User Guide.
- Chiu M, Austin P, Manuel D, and Tu J. Comparison of cardiovascular risk profiles among ethnic groups using population health surveys between 1996 and 2007. CMAJ 2010; DOI:10.1503/cmaj.091676. Available at: http://www.cmaj.ca