Specific Structures (by Topic)¶

This will link through to the DDI Model documentation, each topic needs some form of description / introduction.

Administration¶

A description of what adminstration means ……

DDIInstance
DDIProfile
Group
LocalHoldingPackage
OtherMaterial
ResourcePackage
StudyUnit

Classification¶

ClassificationCorrespondenceTable
ClassificationFamily
ClassificationIndex
ClassificationItem
ClassificationLevel
ClassificationSeries
StatisticalClassification

Comparison¶

Comparison
GenericMap
RepresentationMap

Data Capture¶

DDI-L supports both data capture from questions and measurements. The latter being introduced in DDI-L 3.3.

Questions¶

As the complexity of question structures has increased, three general question structures have been identified within DDI and are addressed by the following specific structures: QuestionItem, QuestionGrid, and QuestionBlock.

Note that all three structures reflect the reusable structure of various question types and do not relay any information on the applied use of the question within an instrument. The applied information, including question order, is captured by the ControlConstruct structures used by the Instrument.

All question structures are maintained within a QuestionScheme and can be further organized for administrative purposes by QuestionGroup (a standard grouping structure available in most schemes). Only QuestionItem, QuestionGrid, and QuestionBlock may be referenced by a QuestionConstruct.

A Sequence (type of ControlConstruct) is used to order questions within an instrument and is maintained separately as a reusable object. All question structures are versionable and contain a name for the question. All response domains may be described inline while a set of commonly used structures may be captured as managed representations and be reused by reference. These include Missing Values, Text, Numeric, DateTime, and Scale.

QuestionItem¶

A QuestionItem is a basic question containing a QuestionIntent, the concept being measured by the question, text for the question, response domain information, clarifying instructions, external aids (clarifying objects used in presenting the question to the respondent), Input and Output Parameters and Bindings, allowed response cardinality and an estimation of the time required to respond. The QuestionText is a DynamicTextString. Note that due to the variation of content in the QuestionText that is required to illicit equivalent responses in different languages, QuestionText is repeatable. A StructuredMixedResponseDomain supports situations where a response may include more than one type of response domain. This could be the inclusion of a set of Missing Values (responses that capture non-response and other values to be treated as invalid during analysis), or the commonly used addition of a text response to capture specific information when the code or category response is “Other”. StructuredMixedResponse allows for the addition of text and/or another response domain to be attached to one or more values of the primary response domain as well as stacking combinations of response options with intervening text.

QuestionGrid¶

A QuestionGrid provides a multidimensional structure used to capture a complex response. In many cases these are simple structures, for example a question regarding an assessment of each of a list of candidates for political office. However, some grids are complex and capture different responses for each of a list of items. In addition, the list may be provided by the question or by the respondent (indicated by the use of a “roster” of blank text items). A QuestionGrid contains the basic elements of the QuestionItem but rather than a ResponseDomain or StructuredMixedResponseDomain contains a GridDimension that sorts one or more ResponseDomains or StructuredMixedGridResponseDomains into a specific dimension of the grid. The structure is similar to the NCube dimensional structure using code domain or roster rather than variables to structure the dimension, and then providing a response domain for each cell in the grid. A single ResponseDomain indicates that this is the response domain for each cell in the grid. Note that an internal cell label may be added to any cell for clarification purposes.

QuestionBlock¶

A QuestionBlock is intended to bundle together a set of questions (items and/or grids) that have meaning only in relation to a specified object expressed as the stimulus material. This form of question set is common in educational testing where a text, image, or other material is provided and the respondent is asked questions specific to the material. For example, a portion of a play script is provided and the respondent is asked question concerning the dialog and/or stage directions provided in the script. Note that the intent of QuestionBlock is NOT to bundle together a set of questions that are commonly used together or used in a specified order.

A Sequence (type of control construct) is the appropriate way to manage this type of set relationship. It is assumed that one or more StimulusMaterial objects will be used. The 0..n cardinality of the CHOICE of StimulusMaterial, QuestionItemReference, and QuestionGridReference is provided simply to support the use of DDI during the development process when this piece of information may be unavailable. StimulusMaterial is part of this choice to allow for its insertion at any location before, after, or in the midst of the referenced Questions.

QuestionBlock contains the standard elements of QuestionItem and QuestionGrid and then structures any combination of StimulusMaterial with referenced QuestionItems and QuestionGrids. It allows for an indication of QuestionSequence (i.e., a means of declaring the sequence is important or that it can be randomized or otherwise altered).

MeasurementItem¶

A MeasurementItem is analagous to a QuestionItem, the difference being that the QuesitonText is replaced by a TypeofMeasurementItem which is a CodeValueType for which a controlled vocabulary mey be used, and a MeasurementItemIntent which is a textual description of what the MeasurementItem is designed to measure.

ControlConstructs¶

The following items are designed to be used to control the flow or processing within an Instrument

ComputationItem
GeneralInstruction
GenerationInstruction
IfThenElse
Loop
MeasurementConstruct
ProcessingEvent
QuestionConstruct
RepeatUntil
RepeatWhile
Sequence
StatementItem
Split
SplitJoin

Other¶

DataCollection
Instrument
Instruction

Data Description¶

ConceptualVariable
DataRelationship
DataSet
LogicalProduct
ManagedDateTimeRepresentation
ManagedMissingValuesRepresentation
ManagedNumericRepresentation
ManagedScaleRepresentation
ManagedTextRepresentation
NCube
PhysicalDataProduct
PhysicalInstance
PhysicalStructure
QualityStandard
QualityStatement
RecordLayout
RepresentedVariable
Variable
VariableStatistics
Weighting
WeightingMethodology

Foundational¶

Category
CodeList
Concept
ConceptualComponent
Individual
Organization
Relation
SubUniverseClass
UnitType
Universe

Geographic¶

GeographicLocation
GeographicStructure

Grouping¶

CategoryGroup
CodeListGroup
ConceptGroup
ConceptualVariableGroup
ControlConstructGroup
DevelopmentActivityGroup
GeographicLocationGroup
GeographicStructureGroup
Group
InstructionGroup
InstrumentGroup
ManagedRepresentationGroup
MeasurementGroup
NCubeGroup
OrganizationGroup
OtherMaterialGroup
PhysicalInstanceGroup
PhysicalStructureGroup
ProcessingEventGroup
ProcessingInstructionGroup
QualityStandardGroup
QualityStatementGroup
QuestionGroup
RecordLayoutGroup
RepresentedVariableGroup
UnitTypeGroup
UniverseGroup
VariableGroup

Schemes¶

Schemes are designed to bring together sets of similar objects (i.e. Variables, Concepts, RecordLayouts, etc.) which are managed as a unit for either conceptual or administrative purposes. Schemes have a common structure providing descriptive information about the scheme, a set of similar objects, and the ability to group those objects for administrative purposes.

CategoryScheme
CodeListScheme
ConceptScheme
ConceptualVariableScheme
ControlConstructScheme
DevelopmentActivityScheme
GeographicLocationScheme
GeographicStructureScheme
InstrumentScheme
InterviewerInstructionScheme
ManagedRepresentationScheme
MeasurementScheme
NCubeScheme
OrganizationScheme
OtherMaterialScheme
PhysicalStructureScheme
ProcessingEventScheme
ProcessingInstructionScheme
QualityScheme
QuestionScheme
RecordLayoutScheme
RepresentedVariableScheme
SamplingInformationScheme
UnitTypeScheme
UniverseScheme
VariableScheme

Study¶

Archive
Group
StudyUnit

Survey Development¶

Includes:

Methodology
Sample
SampleFrame
SampleStep
SamplingInformationGroup
SamplingPlan
SamplingStage
WeightingMethodology

Sampling Procedure has been been extended to link to a Sampling Plan and a specific Sample used during data capture.

Sampling Plan provides both basic information on the intended target population as well as the split and/or stratification rationale generally provided by codebooks for studies using a sample of a population rather than a full census of the population. The Sampling Plan can link to a process (defined by Control Construct subtypes). Two new Control Construct specializations have been added to describe a Sample Step and a Sampling Stage. Sample Step describes requirements for acceptence, stratification description, and any commands or processes needed to perform the sample. Sampling Stage decribes the sampling unit, Sample Frame requirements needed to support the sampling process, probability of selection, and stratification. It may also recommend a Sample Frame that will meet those requirements.

A Sample describes the implementation of a Sampling Plan as well as the specific Sample Frame(s) used. It specifies the population of concern, the overall target sample size as well as actual sample size, the data of the sample, and application details. A Sample can be referenced by a Sampling Procedure, a specific Collection Event, and by Weighting. At its simplist a Sample provides a basic description of the resulting sample, its size and type.

Sampling Plans and Sample Frames can be organized and grouped within a Sampling Information Scheme. They are also capable of capturing complex sample stages including stratification, and experimental design models.

[insert diagram here]

Includes:

Development Activity - CognitiveExpertReviewActivity - CognitiveInterviewActivity - ContentReviewActivity - FocusGroupActivity - PretestActivity - TranslationActivity
DevelopmentImplementation
DevelopmentPlan
DevelopmentResults
DevelopmentStep

The process of creating and testing instruments to capture data through questionnaires, measurement, or reuse of existing data can be complex. Recording this information provides process blueprints and verification for large products as well as valuable information for the user who may need to understand how a question, measurement, or protocal was developed and tested in order to understand the data captured by the final instrument. This approach supports the reuse of tested activities and approaches within a discipline as well as iterations of a Development Plan within a project over time. Data Capture Development incorporates the use of the Lifecyle process model expresses with Control Constructs. It adds one specialized Control Construct (Development Step) and two general use subtypes of Control Construct (Split and SplitJoin) which allow for non-specific sequencing of process steps and actions.

Development work is directed towards specific objects:

Questions: wording, response domain, translation, and instructions
Measurements: choice of measurement devise, calibration, interpretation, response domain, and instructions
Control Construct: algorithm or process used, sequencing, routing, and instructions
Instrument: presentation, mode specific variations, choice of mode, and instructions

The primary objects used to capture development information include:

Development Plan - describes object and cost structure of the plan, the development object, and the Development Activities included in the plan.

Development Activity - has a number of specializations in areas of development that are well developed such as translation work. All specializations describe the desired outcomes, process summary, recommended staff requirements (such as language fluency), other required resources, a debriefing process. This basic information may be the used without having to detail the specific Development Steps taking place in an implementation.

Develpment Implementation - specifies the information of actual development work. What Development Activity was implemented, who performed the activity, and when the action was completed. It can provide detailed information on the steps of the process including internal iterations and valdiation criteria.

Development Step (specialization of a Control Costruct) - implements a Development Activity for a Development Object. It captures information on the prerequisite for the step, conditions for acceptance (when the step is complete and can be exited), and the date of the activity. This can be a single process step or part of a more complex process.

Development Results - describe the final result of a the implementation of a development activity. The objects of the development work can now link to the appropriate Development Results and then follow this back to specific a Development Implementation of a Development Activity.

Note that the process of selection, access to, and reuse of existing data found in registries, administrative data systems, or published data is captured using a Collection Event containing a process description or instrument (such as an API). Data Capture Development can describe the development of single or sequenced Control Constructs expressed individually or within an Instrument.