The 2006 National Health Interview The 2006 National Health Interview Survey (NHIS) Paradata File:Survey (NHIS) Paradata File:

Overview And Applications Overview And Applications

Beth L. TaylorBeth L. Taylor2008 NCHS Data User’s Conference 2008 NCHS Data User’s Conference

August 13August 13thth, 2008, 2008

2006 Paradata File2006 Paradata File

Paradata is information about the dataParadata is information about the data

collection processcollection process

Data collected during and immediately Data collected during and immediately after the NHIS interviewafter the NHIS interview

Part of the NHIS annual data releasePart of the NHIS annual data release

National Health Interview SurveyNational Health Interview Survey

NHIS – Annual survey of the civilian, non-institutionalizedNHIS – Annual survey of the civilian, non-institutionalizedpopulation of the U.S. – sponsored by the National Center for population of the U.S. – sponsored by the National Center for Health StatisticsHealth Statistics

Approximately 35,000 families interviewed annuallyApproximately 35,000 families interviewed annually

In-person interview with telephone follow-up allowedIn-person interview with telephone follow-up allowed

4 ongoing core modules (Household, Family, Sample Child, Sample4 ongoing core modules (Household, Family, Sample Child, Sample Adult) plus annual supplementsAdult) plus annual supplements

Census Bureau (contractor) carries out field work for Census Bureau (contractor) carries out field work for Sponsor NCHSSponsor NCHS

Sources of ParadataSources of Paradata

Contact History Instrument (CHI)Contact History Instrument (CHI)

- Introduced in 2004- Introduced in 2004 - Produced by the Census Bureau- Produced by the Census Bureau - Used on other Census surveys- Used on other Census surveys

- Launches each time interviewer accesses the CAPI - Launches each time interviewer accesses the CAPI instrumentinstrument

- Captures data on each visit attempt- Captures data on each visit attempt - In-scope responding and nonresponding households- In-scope responding and nonresponding households - Out-of-scope households- Out-of-scope households

Contact History InstrumentContact History Instrument

Captures whether attempt via phone or personal Captures whether attempt via phone or personal visitvisit

Contact pathContact path - Description of contact attempt- Description of contact attempt - Reluctance- Reluctance - Strategies used to complete interviews- Strategies used to complete interviews

Noncontact pathNoncontact path - Description of attempt- Description of attempt - Strategies- Strategies

Contact History InstrumentContact History Instrument

Examples of Strategies:Examples of Strategies:

- Advance Letter given- Advance Letter given

- Scheduled appointment- Scheduled appointment

- Left note/appointment card- Left note/appointment card

- Staked-out household- Staked-out household

- Checked with neighbors- Checked with neighbors

Contact History InstrumentContact History Instrument

CHI dataCHI data

- Family-level file - Family-level file - Summary of contacts, noncontacts, strategies - Summary of contacts, noncontacts, strategies

used during interview periodused during interview period

- Attempt-level file- Attempt-level file - Date and time of contact attempt- Date and time of contact attempt - Description of contact, noncontact, reluctance, - Description of contact, noncontact, reluctance,

strategies used for that visit attemptstrategies used for that visit attempt

Sources of NHIS ParadataSources of NHIS Paradata

Front/Back sections of survey instrumentFront/Back sections of survey instrument - Present on NHIS since late 1990’s- Present on NHIS since late 1990’s

- Tailored to NHIS - Tailored to NHIS

- Language of interview - Language of interview

- Cooperativeness of respondent- Cooperativeness of respondent

- Mode of interview (personal visit or phone)- Mode of interview (personal visit or phone)

- Reasons for partial/break-off interviews- Reasons for partial/break-off interviews

- Type of noninterview case- Type of noninterview case

Sources of NHIS ParadataSources of NHIS Paradata

Time fileTime file - Interview times (length of interview start-finish)- Interview times (length of interview start-finish) - Module/Section times (time of 4 core modules and - Module/Section times (time of 4 core modules and

within-module sections)within-module sections)

Audit trailsAudit trails - Record of keystrokes - Record of keystrokes

- Field times (length of time per question)- Field times (length of time per question) - Dates- Dates - Interviewer notes- Interviewer notes

Paradata File CreationParadata File Creation

In early 2007 NHIS Paradata Committee In early 2007 NHIS Paradata Committee established at NCHS to:established at NCHS to:

- Select variables to include on the initial - Select variables to include on the initial Paradata File releaseParadata File release

- Weighed issues of confidentiality, usability- Weighed issues of confidentiality, usability - Example: Created numerous recodes for CHI file - Example: Created numerous recodes for CHI file

variables variables

Paradata File ReleaseParadata File Release

First NHIS Paradata File released in First NHIS Paradata File released in

January, 2008 on the Internet (2006 NHIS data)January, 2008 on the Internet (2006 NHIS data)

125 Variables125 Variables - Family-level file (one record equals one case)- Family-level file (one record equals one case)

Dual usesDual uses - Can be analyzed alone or linked to the 2006 health - Can be analyzed alone or linked to the 2006 health

data filesdata files

Table 1: 2006 Paradata File Frequency Distribution of Cases by OutcomeTable 1: 2006 Paradata File Frequency Distribution of Cases by Outcome

Outcome CodeOutcome Code FrequencyFrequency

Interview CasesInterview Cases

Completed CasesCompleted Cases 24,32324,323

Sufficient Partial CaseSufficient Partial Case 5,8475,847

Type A Cases (nonresponding)Type A Cases (nonresponding)

Language ProblemLanguage Problem 6363

Insufficient Partial CaseInsufficient Partial Case 438438

No One Home, Repeated CallsNo One Home, Repeated Calls 891891

Temporarily Absent, no Follow-upTemporarily Absent, no Follow-up 204204

Refusal CaseRefusal Case 2,1562,156

Other Type AOther Type A 348348

Out-of-Scope CasesOut-of-Scope Cases

Type B: Occupied entirely by Type B: Occupied entirely by

Armed Forces adults, occupied Armed Forces adults, occupied

entirely by persons with Usualentirely by persons with Usual

Residence Elsewhere, Screened Residence Elsewhere, Screened

Out by household (race/ethnicity)Out by household (race/ethnicity)

9,9949,994

TotalTotal 44,264 44,264

2006 Paradata File2006 Paradata File

Internet Release:Internet Release:

Paradata File Description DocumentParadata File Description Document

Variable SummaryVariable Summary

Variable LayoutVariable Layout

DatasetDataset

Sample SAS Input ProgramSample SAS Input Program

Variable FrequenciesVariable Frequencies

2006 Paradata File Release2006 Paradata File Release

File Description DocumentFile Description Document - Sample design- Sample design - Weighting and Variance Estimation- Weighting and Variance Estimation

- Conceptual grouping of variables- Conceptual grouping of variables - Measures of time, contactability, cooperation- Measures of time, contactability, cooperation - Contact strategies- Contact strategies - Partials/Break-offs- Partials/Break-offs - Mode measures- Mode measures - Case-level information- Case-level information

2006 Paradata File Release2006 Paradata File Release

Variable summaryVariable summary - Variable name and brief description of each variable - Variable name and brief description of each variable

on the fileon the file

Variable layoutVariable layout - More detailed description - More detailed description

- Variable universe- Variable universe

- Source (Contact History File, etc.)- Source (Contact History File, etc.)

- Question/Response codes from survey instrument (if - Question/Response codes from survey instrument (if applicable)applicable)

- Notes, recode information- Notes, recode information

2006 Paradata File Release2006 Paradata File Release

ASCII dataset (PARADATA.EXE)ASCII dataset (PARADATA.EXE)

Sample SAS input program Sample SAS input program - Formats - Formats

Variable frequenciesVariable frequencies

Uses of the 2006 Paradata FileUses of the 2006 Paradata File

Stand alone data file (Examples):Stand alone data file (Examples):

- The average number of contact attempts it takes to - The average number of contact attempts it takes to complete the interview complete the interview

- Point in the interview period and time of day when the - Point in the interview period and time of day when the Sample Adult module was started (Early, Middle, Sample Adult module was started (Early, Middle, Late) / (Morning, Afternoon, Evening)Late) / (Morning, Afternoon, Evening)

- Which strategies employed by the interviewer led to - Which strategies employed by the interviewer led to successful completion of the interviewsuccessful completion of the interview

Uses of the 2006 Paradata FileUses of the 2006 Paradata File

Linked to 2006 health microdata (merge with NHISLinked to 2006 health microdata (merge with NHISSample Adult File, Family File, etc.)Sample Adult File, Family File, etc.)

- Item of note: Will not have a 1:1 match with - Item of note: Will not have a 1:1 match with health files because Paradata File has health files because Paradata File has information on nonresponding & out of scope information on nonresponding & out of scope casescases

- Paradata File has a slightly larger number of - Paradata File has a slightly larger number of interviewed cases than health files interviewed cases than health files

- Paradata is field data before cleaning- Paradata is field data before cleaning

Uses of the 2006 Paradata FileUses of the 2006 Paradata File

Examples of possible research using linked Examples of possible research using linked

filesfiles

- Characterizing the characteristics of hard-to-- Characterizing the characteristics of hard-to-contact familiescontact families

- Modeling the impact of the interview mode on - Modeling the impact of the interview mode on health outcomeshealth outcomes

Weighting Weighting

When using the Paradata File as a stand-alone When using the Paradata File as a stand-alone file, use the WTIA_PD variable if making file, use the WTIA_PD variable if making population inferencespopulation inferences

- This weight reflects the probability of household selection - This weight reflects the probability of household selection

When using the Paradata File to support analyses When using the Paradata File to support analyses with the health data files, use the weight variable from thewith the health data files, use the weight variable from thehealth data filehealth data file

- Example: Use WTFA_SA when merging with the Sample Adult - Example: Use WTFA_SA when merging with the Sample Adult FileFile

Variance EstimationVariance Estimation

NHIS data are obtained through a complex sampleNHIS data are obtained through a complex sampledesign involving stratification, clustering, and design involving stratification, clustering, and multistage samplingmultistage sampling

- Recommended that users utilize computer software - Recommended that users utilize computer software that provides the capability of variance estimation and that provides the capability of variance estimation and hypothesis testing for complex sample designs hypothesis testing for complex sample designs (SUDAAN)(SUDAAN)

- PSU and STRATUM variables included on Paradata - PSU and STRATUM variables included on Paradata FileFile

Current NCHS Research Current NCHS Research Using NHIS ParadataUsing NHIS Paradata

Assessing data quality from the field Assessing data quality from the field - Started Quality Assurance Workgroup jointly with - Started Quality Assurance Workgroup jointly with

Census Bureau to monitor data qualityCensus Bureau to monitor data quality

Upcoming presentations Upcoming presentations

Future StepsFuture Steps

2007 Paradata File released in June, 20082007 Paradata File released in June, 2008 - Nearly identical to 2006 Paradata File release- Nearly identical to 2006 Paradata File release

- Telephone items revised for 2007- Telephone items revised for 2007

Expansion for 2008 NHIS Paradata ReleaseExpansion for 2008 NHIS Paradata Release

- To include data from visit-attempt file, possibly audit - To include data from visit-attempt file, possibly audit trail data (use of function keys, language of interview)trail data (use of function keys, language of interview)

Feedback from data usersFeedback from data users

NHIS Paradata FileNHIS Paradata File

For more information about the NHIS For more information about the NHIS Paradata File, please visit:Paradata File, please visit:

http://www.cdc.gov/nchs/about/major/http://www.cdc.gov/nchs/about/major/

nhis/2006paradata.htmnhis/2006paradata.htm