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A logic definition is a logical test that is either "true" or "false", and describes a subset of respondents who gave a particular response to one or more questions.
A filter entry is an entry that contains a logic definition, and has a name, so this subset of respondents can be referred to using the filter entry name.
Filter entries can be:
•Applied to questions and appear on printed questionnaires
•Applied to variables
•Referred to in other logic definitions when:
•defining new filter entries
•defining responses to a single-coded or multi-coded variable
•defining a subset of respondents (base) for analysis
•Stored in the data file, false as 0, true as 1, if the data location is set
•Marked as a hold filter, see below
IMPORTANT: filters are used to control which questions are skipped during data input. Filters should not be confused with question routing, see User guide, Defining a questionnaire, Question details.
For information on naming filters, see User Guide, Inserting entries.
Filter contents are set by the program and recalculated whenever necessary.
Filter contents can optionally be stored in the raw data file (ASC) as 0 (false) or 1 (true) . This is useful when exporting to SPSS and other programs.
There are two types of filter that can be applied to questions:
•Question filters dictate which respondents should be asked the question, if any filter entry applied is false then the question will be routed past and left empty
•Response restrictors dictate which responses should be available to the respondent, if any response restrictor applied has a false response, then this response is not available
You can use both types of filter on the same question.
You can also apply a response filter to individual responses in a question.
Filter entries can also be applied to variables. The variable will be left empty if any filter entry applied is false.
Once defined, a filter can be used as often as required.
To apply a filter, see User guide, Defining a questionnaire, Question details.
To apply the same filter or restrictor to a number of entries, use the Applied filter block update.
If more than one filter or restrictor is applied to an entry they are sorted into entry sequence order.
Using the [Hold input if true] selection it is possible to stop data entry, if the filter definition is true.
TIP: if filters have been applied to the questions being checked, it is usually necessary to repeat the definitions from the question filters in the hold filter.