List of columns

(1) Identifier: The first four columns identify are question. Please note that a question can consist of multiple items. In this case the first item is considered to be the root element and the item is either empty or “root”.

Column Description
study Name of the study (primary key).
questionnaire Name of the questionnaire (primary key).
question Name of the question (primary key).
item Number of the question item (primary key). If the item is empty, the question is considered to be a “root question”, which might have items.

(2) Content: The following columns represent the content of a question or item

Column Description
number Question number (integer), as a reference to the position in the questionnaire.
text Question text.
instruction Interviewer instruction.
answer_list Name of the list of answers (foreign key). The answers.csv.
scale Scale (see list of scales below) of the answers.
filter Incoming filters (see definition below).
goto Outgoing filters (see definition below).
label Label (DEPRECATED).
description Human readable description including additional unstructured information.
concept Name of question’s concept (foreign key). In DDI on Rails the primary link from a question to one or multiple concepts is through the question’s logical variables. Nevertheless, it is possible to link a question or an item directly to a concept.

(3) Links to logical variables and concepts (import only): A question can be linked to multiple logical variables. Therefore, DDI on Rails stores this link with the logical variables. Yet, the questions import allows to link every question to one logical variable.

Column Description
logical_dataset Logical dataset name (foreign key).
logical_variable Logical variable name (foreign key).

(4) Export only: There is a couple of columns that is included in the export but will not be imported.

Column Description
view_sort_id Sort order of the questions. The view_sort_id is generated from the order of the questions in the import file.
view_lft and view_rgt Export only.
view_import_note Export only (DEPRECATED).
view_first_concept Concept of the question, based on the first related variable.
view_import_typ Export only (DEPRECATED).
view_calculated_number and view_calculated_item Special information for imports following the SOEP-QLIB-conventions.
logical_variable Name of the resulting variable (foreign key, import only).
logical_dataset Name of the dataset of the resulting variable (foreign key, import only).

(5) Namespaces (neither imported nor exported): Every study can add an arbitrary number of columns to store additional information that are not intended to be imported in DDI on Rails. Those columns are prefixed with internal_


Code Meaning
txt Only display the text, no variables are generated. All filters and instructions still apply.
chr Result is a character string.
int Result is a integer.
dec Result is a number with decimals.
bin Result is either true, false (equals “null”)
cat Result is a pre-defined answer category. See answer_list for possible answers.

Rules for filter and goto

Filter and goto definitions consist of question names and symbols only,
no keywords (e.g. “goto”) are used.

  • Symboles ( ) = < > @ | & : != <= >=
  • Filter (AGE > 20) & (SEX = 1) means: this question is asked if “age” is
    greater than 20 and “sex” is 1
  • Goto (2 @ TARGET) means: if the answer to the current question is 2 then
    go to question “target”
  • Refer to items using the colon as a seperator, e.g. (PSOR:2 = 3).
  • Value lists and ranges: (x = 1:3) is equal to (x = 1,2,3) is equal to (x = 1) | (x = 2) | (x = 3)