Meeting the Challenge

The National Population Health Survey and Data Access

E. HamiltonUNB LibrariesIASSIST 2003

Outline NPHS: Background &

Confidentiality Challenges

NPHS Products Dissemination

Evaluating Success of Strategy

Concluding Observations

Canadian Context

Federal/provincial/territorial division of powers and responsibilities

Health and privacy legislated at the federal level and at the provincial level

Canadian Context NPHS dissemination affected by:

Statistics Canada Act and policies Privacy Act Privacy legislation at provincial levels Ethics in research guidelines

NPHS Background

NHIC Task Force on the State of Health Information in Canada (1990-91)

Identification of data gaps and related problems in sharing health information

Proposal for a national health survey to provide more comprehensive information on population health status

NPHS Objectives

To provide measures of health status for policy

To provide data for analytic studies To provide panel data to reflect dynamic

process of health and produce periodic cross-sectional estimates

To provide provinces with survey capacity to supplement content or sample

To allow the possibility of linking survey results to administrative data

Risks … More complete information being

collection

Tools and techniques available to amass personal information

Increase in “market potential” of personal information

Potential for misuse of health information

Difficulty to control information use

Any data safety breach potentially serious to mandate of ethical data collectors

At the time of NPHS design, 67% of Canadians said they would oppose free sharing of health care information

And yet…

In the NPHS conducted in 1994/95:

94% of survey respondents consented to have their data linked with administrative health records

96% consented to have data shared with provincial ministries of health.

Between cycle 1 and cycle 2, NPHS retained 93% of longitudinal sample

NPHS Administration Household survey: general and health

components Complex survey design using strata and

based on LFS frame; Respondents to be followed for 20 years

Institutional survey

Northern survey

Cycle 1 Household survey in the field in June 1994

NPHS Products Methodology and survey

documentation, articles in Health Reports, aggregate statistics in national “health report card”

Data products in variety of formats

Workshops, grants, and seminars

NPHS Data ProductsYear Survey Maste

rShare*

PUMF Comments

1994/95

Household (both files)

Yes Yes Yes Suppl. survey data available in all flavours. Dummy file for remote access for Health file

Institutional Yes Yes Yes

Northern Yes Yes No

1996/97

Household (both files)

Yes Yes Yes Longitudinal file for cycle 1 & 2 Dummy files for remote access

Institutional Yes Yes Yes

Northern Yes Yes No

1998/99

Household (both files)

Yes Yes Yes Dummy files for remote access

Institutional Yes Yes No

Northern Yes Yes No

2000/01

Household (both files)

Yes Yes No Longitudinal only; end of PUMFs; dummy files for remote access

Institutional Yes Yes No

Northern Yes Yes No

 Service

Statistics Canada Website

Depository Service Program

Data Liberation Initiative

Sales & Customized Tabulations

Remote Job

Submission

Research Data

Centres

 Who is eligible

General public

 General public through DSP libraries

Post-secondary academic staff & students

Individuals or organizations

Researchers with accepted proposals

Approved researchers

 Conditions

 Available on the Internet at www.statcan.ca

 Available on site

Restricted to teaching and research purposes

Contractual; standard fees usually apply

Arrangement between STC & researcher; fee charged

SSHRC peer review & deemed STC employee status

 Products

- The Daily - Canadian Statistics- Census- Community profiles- Downloadable publications

- Paper publications- Electronic publications & select CDs

Standard data products: aggregate databases, public use microdata files, and geography files

Standard data products; custom tables that have been processed by STC;access to specialized databases

Analytic syntax built by researcher using synthetic files, and STC processing

Confidential data files from the longitudinal surveys begun in the 1990’s, such as the NPHS, SLID, NLSCY

 Notes

Warning: some services on the web site are fee-based

Some DSP libraries provide off-site access to authenticated users

Interface to CANSIM I and Trade Analyzer available through CHASS (University of Toronto)

Specialized databases include CANSIM II and the Trade Analyzer

Available for only select surveys; this service most developed for the NPHS

Applications can be submitted through the RDC/SSHRC web site

Continuum of Access to Statistics Canada Products

Challenges?

•Multistage cluster sample design increases complexity (bootstrap weighting and the problem of variance)

•Attrition in population in Institution survey

•Linkage issues for administrative units and files

•Supplement questions and buy-ins (and you thought life was complicated enough!)

Research Project

Research Objective: to discover evidence of use of the NPHS, a

longitudinal survey by Statistics Canada with significant confidentiality challenges

Methodology:Using established peer-reviewed databases as well as grey literature searching techniques, sought out evidence of data use and knowledge transfer relating to the NPHS

Research Findings

557 Items and counting!

271 articles 105 unique journal titles 147 primary authors of articles

115 conference presentations/reports

31 theses / dissertations

Research Findings

0

50

100

150

200

250

Cross-sectional

Longitudinal Share/linked Both

PUMFs received greatest use in file types identified

0

50

100

150

200

250

300

Cycle 1 Cycle 2 Cycle 3

Cycle 1-3

Cycle 3

Cycle 2

Cycle 1

Cycle 1 remains file with most research use*

* Cited twice in 2003

Research FindingsArticles by year

0

10

20

30

40

50

60

70

80

90

1995 1996 1997 1998 1999 2000 2001 2002 2003

HHD cycle1

PUMF release

HHD cycle2

PUMF release

HHD cycle3

PUMF release

CCHS cycle 1.1

PUMF release

Observations NPHS is a success story in getting data

into the hands of analysts

Though concerned with privacy, respondents trust Statistics Canada enough to allow sharing of data

Complexity in design posed challenges for cross-sectional data file to preserve confidentiality

Observations Challenge with linkage & confidentiality related to

recipient community (priorities, laws, protocols)

Longitudinal file resolved through provision of dummy files for remote job submission & RDCs

Cross-sectional analysis for lower levels of geography now available through CCHS

Despite remarkable research outcomes, no reported breaches in confidentiality by research community

Future Research Completion of grey literature tracking for

NPHS to date

Monitoring RDC analytical output

Tracking CCHS research output

Identifying further “Best Practices” in data dissemination designed to enhance access to data while protecting confidentiality

There is more to come…

Thank you for your attention!