Survey Data Management and the Combined Use of DDI and SDMX

Arofan GregoryChris Nelson

Metadata TechnologyEurostat, June 4-6 2013

Overview

• Eurostat is currently working on an end-to-end example of how SDMX and DDI could be used together in the contenxt of the collection of the Labor Force Survey– Using DDI to describe a questionnaire (from ISTAT)– Describing the collected microdata and its

processing using DDI– Mapping the tabulated DDI to SDMX– Reporting and disseminating the SDMX data

Overview (Cont.)

• For the survey questionnaire, we will look both at the LFS example, but also at work currently being done at INSEE using DDI

• The rest of the work-flow will be presented using slides and demos, both for DDI and for SDMX

• There is a direct mapping between SDMX and DDI, and this will also be presented

Describing the LFS Questionnaire with DDI

The Questionnaire

• We are using the questionnaire as developed by ISTAT for collecting national LFS data

• It has several modules, with complex flows based on respondent’s employment status

The ISTAT Questionnaire

Analysis of the Questionnaire

• The questionnaire has a number of elements:– Question text– Response domains– Statements– Flow logic– Interviewer instructions

• These can all be modelled in DDI

Questions and Response Domains

• DDI supports many types of response domains– Codes– Categories– Numeric– Textual– Date and time

• All of these are used in the LFS questionnaire

QuestionScheme

QuestionItem

CodeDomain

CodeScheme

CategoryScheme

Code 1

Code 2

Code 3

Category “Yes”

Category “No”

Category “Maybe”

Flow Logic

DDI Flow Logic Description

• DDI uses a series of “control constructs” to model flow logic– Statements– Question References– Conditional logic (IfThenElse, loops, sequences,

etc.)– References to Interviewer instructions

• The Questions and Interviewer instructions are held separately, in Schemes

The Instrument

• The Instrument (in DDI) represents the actual questionnaire

• It references the top-level sequence of the flow logic

DDI Packaging Elements

INSEE Use Case