Centers for Disease Control and Prevention

NCHS Research Data Center

Wilbur C. Hadden

What is the Research Data Center?

• A NCHS data access program• An office, with staff, within NCHS• A physical space, with security• A research facility, with

computers

Access to NCHS Data

• Public use data files• Restricted access• Tabulations• Reports, publications, web-site• Journal articles

Authority for Confidentiality

• Public Health Service Act, section 308(d)

• Informed consent of survey participants and data providers

Identified Data

• Data records are identified by unique data elements • Name• Social Security Number• Hospital ID number

Identifiable Data

• Data are made identifiable with data elements that can be related to unique identifiers• Address• Size – e.g. number of beds, height• Specialization – e.g. having a level 1

shock trauma center, or being a farm owner/manager

Statistical Disclosure

• When information on data providers can be inferred from published data

Data Accessible in RDC

• Data that are potentially identifiable

• Physician age and sex in NAMCS• Data linked to geographic identifiers• State, county, Census tract

• Data linked to provider characteristics• Hospital size

RDC Data Access Methods

• On-site access• Remote access• RDC staff assistance /

collaboration

Data Preparation

• Users cannot take data into RDC• RDC staff prepare data files for

users• Users can provide data to RDC staff• NCHS policy is not to release user

data to others• RDC staff will link user data to

NCHS data

On-Site Access• Controlled access facility• Isolated computer network• No e-mail• No internet

• No mountable media on computers• Users cannot take materials into

computer room• No more than 3 users per project

Output Disclosure Review

• Only printer is located behind locked door• RDC staff person retrieves

output• Disclosure review performed

before output given to users

Remote Access

• Send SAS programs to RDC by e-mail• SAS program scanned – a few SAS

commands and not allowed• Program executed• Automated disclosure review of

program output• Output returned by e-mail

Software in RDC

• SAS (only language available on ANDRE)

• SUDAAN• Fortran• HLM• Stata• Limdep• text editors/viewers

To Gain Access to NCHS RDC

•Visit the RDC (optional, but suggested)•Discuss proposal with RDC staff•Submit research proposal•Discuss proposal with RDC staff and revise•Pass NCHS review of proposal•Sign “Research Affidavit of Confidentiality”

Proposal Contents

• Identification of researcher(s)• Source of funding• Description of proposed research• Detailed specification of data sought• Detailed specification of any user

supplied data• Software requirements

Proposal Evaluation Criteria

•Risk of disclosure of confidential data•Scientific merit and technical feasibility•Availability of resources in RDC•Consistency with NCHS mission

Cost per Project

File construction and setup

$500 per day

On-site $1000 per week

Remote Access NSFG-CDF $500 per year NHIS-polio $500 per year Files < 130k records $500 per

month Files > 130k records $1000 per

month

Number of RDC Clients

2000 2001 2002*

Remote Access 7 3 3On Site 4 10 11Staff Programming 1 1 5

*January to July 2002

Jobs Processed at RDC

2000 2001 2002

*Remote Access 888 441 456

On Site 570 1006 1645Staff Programming 81 212 760

*January to July 2002

Projects by Data System

2000 2001 2002*

NHIS 6 7 8NSFG 3 7 8NHANES 1 2 1NAMCS 1 1 4Other -- 2 5*January to July 2002

http://www.cdc.gov/nchs/r&d/rdc.htm