2002 NSAF Data Editing and Imputation

Report No. 10 in the 2002 NSAF Methodology Series

The nonpartisan Urban Institute publishes studies, reports, and books on timely topics worthy of public consideration. The views expressed are those of the authors and should not be attributed to the Urban Institute, its trustees, or its funders.

Note: This report is available in its entirety in the Portable Document Format (PDF).

Introduction

The National Survey of America's Families (NSAF) was developed out of a need for empirical data to respond to major changes in welfare policy at the federal and state levels. The Urban Institute and Child Trends combined their expertise in welfare policy with the data collection efforts of Westat, an experienced survey firm.

By the third (2002) round of NSAF, many of the data handling problems encountered in the first two rounds of data collection had been minimized, and proven data handling approaches were implemented with few changes. This report describes those procedures unique to the third round. To read about the data editing efforts of rounds one and two please see Report 10 in the 1997 and 1999 NSAF Methodology Series.

Data Editing and Data Coding

The data editing process for the 2002 NSAF consisted of three main tasks: handling problem cases, reading and using interviewer comments to make data updates, and coding questions with text strings. Extensive quality control procedures were implemented to ensure accurate data editing and coding.

Before delivering the data, Westat did much of the data editing involving interviewer comments as well as fixing cases that were designated as problematic by the telephone supervisor. Additionally, the Urban Institute staff developed a series of programs that checked the consistency of each question item by section of the questionnaire as well as general program checks that tested for item consistency on subjects such as family relationships, immigration status, and age of respondents. These section and general program checks often uncovered problems that required going back to the interviewer comments or problem case notes in order to resolve.

Except for the coding done at the Census Bureau of industry and occupation, all the post-survey editing and assignment of codes fo r open-ended questions for the 2002 NSAF was done at the Urban Institute. "Other specify" questions were those in which a question had some specific answer categories but also allowed text to be typed into an "other" category. Open-ended questions had no pre-coded answer categories. Westat and the Urban Institute had developed an interactive process for defining these categories during round 1. It was this structure that formed the basis for much of the coding done for the 2002 survey. Often, for "other specify," we were able to start with the exact decisions made in round 1 for a respondent comment.

Because data editing and coding update the data, careful quality control procedures were implemented at Westat and at the Urban Institute. These measures involved limiting the number of staff who made updates, using flowcharts to diagram complex questionnaire sections, frequent consulting meetings, carefully checking updates, and conducting computer checks for inconsistencies or illogical patterns in the data.

Data edits and open-ended and other specify coding make up the bulk of the data development work needed to produce the analytical files. However, this oversimplifies the work needed to produce analytical files. At the end of this report is a flow chart tha t displays how highly structured the overall NSAF data development process was. This diagram starts with the raw interview data and ends with nine analytical public use data files. In addition to coding and editing the NSAF data development process relies on imputation methods to account for much of the item missing data.

Note: This report is available in its entirety in the Portable Document Format (PDF).

The nonpartisan Urban Institute publishes studies, reports, and books on timely topics worthy of public consideration. The views expressed are those of the authors and should not be attributed to the Urban Institute, its trustees, or its funders.

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