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Action Tags Conditional IF

Action Tags — @IF: Conditional Action Tag Logic

Article ID RC-AT-08 — Action Tags: @IF — Conditional Logic
Domain Action Tags
Applies To All REDCap project types; requires Project Design and Setup rights
Prerequisite RC-AT-01 — Action Tags: Overview; familiarity with branching logic syntax
Version 1.0
Last Updated 2026
Author See KB-SOURCE-ATTESTATION.md
Related Topics RC-AT-01 — Action Tags: Overview; RC-AT-02 — @HIDDEN & @READONLY — Visibility Control — @HIDDEN & @READONLY; RC-AT-03 — Radio & Dropdown Action Tags; RC-AT-06 — Autofill Action Tags; RC-BL-01 — Branching Logic: Overview & Scope

1. Overview

@IF is a meta action tag that applies different action tags to a field depending on a logical condition. Instead of hard-coding a single behavior for a field, @IF evaluates a condition when the page loads and then activates one set of action tags if the condition is true and a different set if it is false.

This allows a single field to behave differently for different records, users, data access groups, or events — without building separate instruments or using branching logic workarounds.

Important: The condition inside @IF is evaluated once when the page loads. It is not re-evaluated in real time as the user enters data on the page.

2. Key Concepts & Definitions

Condition

A logical expression using the same syntax as REDCap branching logic — e.g., [field_name] = '1'. Both field variables and Smart Variables may be used. The condition evaluates to true or false at page load.

True branch

The action tag(s) to apply when the condition evaluates to true. Multiple action tags can be listed, separated by spaces.

False branch

The action tag(s) to apply when the condition evaluates to false. Use an empty pair of quotes ('') as a placeholder if no action tags should apply in the false case.

3. Syntax

@IF(condition, action_tags_if_true, action_tags_if_false)
  • The condition uses standard branching logic syntax.
  • The true branch and false branch are separated from the condition and from each other by commas.
  • To apply no action tags in one branch, use '' (two apostrophes or two double-quotes) as a placeholder.
  • To apply multiple action tags in a branch, list them separated by spaces — do not use commas between tags within a branch.

4. Examples

4.1 Simple Case — Hide or Show

Hide a field for records in one data access group; leave it visible for all others:

@IF([dag-name] = 'site_a', @HIDDEN, '')

When the condition is true (the current record is in DAG "site_a"), the field is hidden. For all other records, no action tag is applied and the field displays normally.

4.2 Multiple Action Tags in One Branch

Apply both @HIDECHOICE and @READONLY when a condition is met:

@IF([status] = '1', @HIDECHOICE='3' @READONLY, '')

When status equals 1, choice 3 is hidden and the field is read-only. Note that @HIDECHOICE='3' and @READONLY are separated by a space inside the branch — not by a comma.

4.3 Different Behavior in Each Branch

Apply one action tag when true and a different one when false:

@IF([consent] = '1', @READONLY, @HIDDEN)

If consent is recorded, the field is read-only (visible but not editable). If consent is not yet recorded, the field is hidden entirely.

4.4 Nested @IF

@IF can be nested inside another @IF to handle more than two conditions:

@IF([role] = '1', @HIDDEN, @IF([role] = '2', @READONLY, ''))

For role 1: hidden. For role 2: read-only. For all other roles: no restriction.

4.5 Multiple @IF on the Same Field

Multiple independent @IF tags can be placed on the same field, separated by spaces. All conditions are evaluated independently at page load:

@IF([site] = 'east', @HIDDEN-SURVEY, '') @IF([lang] = 'fr', @READONLY, '')

5. PDF Behavior

@IF is also evaluated when generating a PDF of an instrument or survey. This means PDF-specific action tags (such as @HIDDEN-PDF) can be placed inside @IF branches and will be applied correctly in the generated PDF.

6. Limitations

Not evaluated in real time. The condition is checked once when the page loads. If a user changes a field value that the condition depends on, @IF will not re-evaluate until the page is reloaded.

Do not use @CALCTEXT or @CALCDATE inside @IF. The calculation action tags operate in contexts (real-time recalculation, data import, Data Quality rules) that @IF does not. Placing them inside an @IF branch produces unexpected results. See RC-AT-09 — Action Tags: @CALCTEXT & @CALCDATE — Calculations for guidance on calculation tags.

Avoid complex nesting. Deeply nested @IF statements are difficult to read and maintain. If logic becomes complex, consider restructuring the project design or using branching logic to control field visibility separately.

7. Common Questions

Q: Can I use Smart Variables in the @IF condition?

A: Yes. Both field variables (e.g., [age]) and Smart Variables (e.g., [user-dag-name]) are valid in the condition. This makes it possible to apply different action tags based on the current user's role, DAG membership, or event.

Q: Does @IF work in surveys?

A: Yes. The condition is evaluated when the survey page loads, using whatever data is available for that record at that point in time.

Q: What happens if both the true and false branches are empty?

A: Using '' in both branches (@IF([field]='1', '', '')) has no practical effect — no action tags are applied in either case. This is valid but unnecessary.

Q: Can @IF be combined with other action tags placed directly on the field (outside @IF)?

A: Yes. A field can have both standalone action tags and @IF tags. The standalone tags always apply; the @IF tags add or layer additional behavior conditionally.

8. Common Mistakes & Gotchas

Using commas to separate action tags within a branch. Tags inside a branch must be separated by spaces, not commas. @IF([x]='1', @HIDDEN, @READONLY-SURVEY @HIDDEN-PDF, '') is incorrect because the false branch appears to have two items separated by a comma. Write it as @IF([x]='1', @HIDDEN, @READONLY-SURVEY @HIDDEN-PDF) or use '' as a placeholder: @IF([x]='1', @HIDDEN, '').

Expecting real-time re-evaluation. @IF evaluates at page load only. A field that is hidden by @IF based on another field's value will not become visible if the user changes that other field during the same session — the page must reload.

Nesting @CALCTEXT or @CALCDATE inside @IF. This combination is explicitly not supported. Use calculation action tags directly on the field without wrapping them in @IF.

Forgetting the '' placeholder. If one branch should apply no action tags, use '' as an explicit placeholder. An empty branch (missing parameter) causes a syntax error and the tag will not function.