Methods of the study engine

Study engine

The study engine is the core component of the study running on the server. Its main responsibility is to handle study events based on each study's own rule set.

When a specific event occurs (e.g. a participant submits a survey), the study engine evaluates the participant's data against the study's rules and executes the appropriate actions. These rules encode the study flow. The engine supports a large set of actions and expressions, providing a high level of freedom in the study design.

Actions: typically used to mutate the participant's state, e.g. assign a survey, send a message, create a report, etc.

Expressions: typically used to evaluate the participant's state, e.g. check if the participant has a specific flag, check if the participant has answered a specific question, etc.

Example of a conditional rule:

Condition: Participant's age is less than 18. -> expression comparing a numeric value against a threshold
Action: Set the participant's age category to child. -> action setting a participant flag

Logical Expressions

Expressions are used to evaluate the participant's state and return a boolean (true/false), number, or date value.

Logical Operators

Logical conditions allow you to combine multiple expressions into more complex rules. They include AND, OR, and NOT, which determine whether all, any, or none of the specified conditions must be true. Example: assign a test kit only if the participant has clicked the Order button AND has given consent.

Comparisons

Comparison conditions check whether a value associated with the participant (e.g., responses, context variables, participant flags, or dates) matches or differs from another value. The value on the right side can either be a fixed input or another participant associated value. They include equals, less than, less than or equal, greater than, and greater than or equal. Use these when you want rules to trigger only if study data falls inside or outside specific thresholds. Example: Assign a follow-up survey only if the participant’s age flag is greater than or equal to 18.

Event Properties

1. Check event type

Meaning: True if the event matches a specific type (e.g., submit, timer, custom...).
Use Case: Run action only for certain event categories.
How it works: Select the event type.

2. Current event is submission of survey with key

Meaning: True if the event is the submission of a defined survey.
Use Case: Trigger actions only when a specific survey is completed.
How it works: Enter the survey key.

3. Custom event with key

Meaning: True if the event is a custom one identified by its key.
Use Case: React to special user actions or system events.
How it works: Provide the custom event key.

4. Has (any) event payload

Meaning: True if the event contains additional data.
Use Case: Run actions only when extra information is attached.
How it works: No input required.

5. Has event payload with key

Meaning: True if the payload includes a given key.
Use Case: Check for specific structured data in the event.
How it works: Enter the key to check.

6. Has event payload with key and value

Meaning: True if the payload contains a key with a matching value.
Use Case: Filter events by exact data content.
How it works: Enter both key and expected value.

Study variables

1. Get study variable as boolean

Meaning: Retrieves the value of a study variable and returns it as a boolean (true or false).
Use Case: Useful for evaluating binary conditions such as visibility of certain components or surveys, eligibility, or activating study flows.
How it works: Provide the variable key.

2. Study variable string equals

Meaning: Compares the value of a study variable (as a string) to a specified string and checks for equality.
Use Case: Ideal for branching logic or conditional workflows based on group assignments, study phases, or other string-based values.
How it works: Provide the variable key and the string to compare.

Advanced

1. Is study code present

Meaning: True if a specific study code has been assigned to the participant.
Use case: Use when actions should only apply to coded participants.
How it works: Select the study code to check for.

Templates

1. Study variable string equals

see Study variables

Response checkers

1. Response contains any of these keys

Meaning: True if a participant’s response includes one of the specified keys.
Use case: Use when multiple acceptable responses can trigger the rule.
How it works: Provide the item key and a list of slot keys.

2. Has response but none of these keys

Meaning: True if a response exists but excludes specific keys.
Use case: Use when certain answers should be filtered out.
How it works: Provide the item key and a list of slot keys to exclude.

3. A specific response key is present

Meaning: True if a specific response key is included in the participant’s answer.
Use case: Use when rules should depend on the presence of a particular question or item.
How it works: Enter the response item and slot key to check for.

4. A specific response key is present and has a specific value

Meaning: True if a response key matches a defined value.
Use case: Use when precise matching of responses is required.
How it works: Provide the item and slot key and enter the expected value.

5. Check condition for old responses

Meaning: True if past participant responses from older surveys meet the specified condition.
Use case: Use when rules should evaluate historical responses, for example to detect repeated patterns.
How it works: The condition checks stored responses within an optional time window defined by "responses since" and "responses until". You can choose whether all, any, or a minimum count of responses must fulfill the condition.

Meaning: Checks if the participant has provided consent.
Use case: Use when study actions must only apply to consenting participants.
How it works: Provide the consent key to check.

Participant state checkers

1. Has a survey with key assigned

Meaning: True if the participant has a specific survey assigned.
Use Case: Check whether a survey is already linked to the participant.
How it works: Enter the survey key.

2. Is survey in active window (template)

Meaning: True if the assigned survey is currently available for the participant.
Use Case: Trigger actions only while the survey is available to complete.
How it works: Provide the survey key and the reference time (e.g., current time) to compare it against the survey’s assigned start and end timestamps.

3. Survey assignment start is before reference time (template)

Meaning: True if the survey’s assigned start time is earlier than the chosen reference time.
Use Case: Trigger actions only after a survey has become available.
How it works: Provide the survey key and a reference time (e.g., current time or a calculated timestamp).

4. Survey assignment end is before reference time (template)

Meaning: True if the survey’s assigned end time is earlier than the chosen reference time.
Use Case: Trigger actions after a survey’s availability window has ended.
How it works: Provide the survey key and a reference time (e.g., current time or a calculated timestamp).

5. Has study status

Meaning: True if the participant has the defined study status.
Use Case: Apply rules depending on participant’s current study role or status.
How it works: Select the study status (e.g. "active", "inactive", "finished", "exited").

6. Has participant flag key

Meaning: This condition evaluates to true if a participant has a flag with the specified key, regardless of its value.
Use Case: Useful when you want to check if a participant has been assigned a certain flag without caring about what the value is.
How it works: Enter the key of the participant flag you want to check.

7. Has participant flag key and value

Meaning: True if the participant has a specific flag with a matching value.
Use Case: Target participants based on custom flags or metadata assigned to them.
How it works: Enter both the flag key and expected value to match against participant flags.

8. Has linking code

Meaning: True if the participant has been assigned a linking code.
Use Case: Use when rules should apply only to participants connected across studies or systems.
How it works: Select the linking code to check for.

9. Last submission date is older than

Meaning: True if the participant’s most recent submission occurred before a specified date.
Use Case: Use to identify inactive participants or trigger reminders after a period of inactivity.
How it works: Enter a cutoff date (and an optional survey key); condition is true if the last submission (of the survey key) is earlier than that date.

10. Has message type assigned

Meaning: True if a specific message type has been assigned to the participant.
Use Case: Use when actions should only trigger for participants who are linked to a certain message type (e.g. reminder).
How it works: Select the message type to check for.

Incoming participant state checkers (for merge events)

1. Incoming state has survey with key assigned (Merge event)

Meaning: True if the temporary participant state being merged includes a survey with the specified key.
Use Case: Handle cases where merged participants bring survey assignments that need to be processed or validated.
How it works: Enter the survey key.

2. Has incoming study status (Merge event)

Meaning: True if the incoming participant has a specific study status assigned.
Use Case: Apply rules only when the incoming participant has a defined study status (active, inactive, finished or exited).
How it works: Select the study status (e.g. "active", "inactive", "finished", "exited").

3. Has incoming participant flag key and value (Merge event)

Meaning: True if the incoming participant has a flag with the specified key and value.
Use Case: Use when merging should consider specific flags states from the incoming account.
How it works: Enter the flag key and value.

4. Has incoming participant flag key (Merge event)

Meaning: True if the incoming participant has a specific flag key defined, regardless of its value.
Use Case: Use when the presence of a flag alone should affect merge actions.
How it works: Enter the flag key.

5. Incoming last submission date is older than (Merge event)

Meaning: True if the incoming participant’s last submission occurred before a specified date.
Use Case: Handle merges differently based on how recently the incoming participant was active.
How it works: Enter a cutoff date (and an optional survey key); condition is true if the incoming last submission (of the survey key) is earlier than that.

6. Has incoming message type assigned (Merge event)

Meaning: True if the incoming (temporary) participant has a specific message type assigned.
Use Case: Use when actions should only apply if the incoming account already carried a certain message type (e.g., invitation, reminder).
How it works: Select the message type to check for.

7. Has incoming linking code (Merge event)

Meaning: True if the incoming participant has a linking code assigned.
Use Case: Apply rules that depend on participants already being linked across studies or external system connections.
How it works: Select the linking code to check for.

Numbers and Dates

Some expressions return numbers and dates that can e.g. be used for comparisons. Note that Dates are always represented in Unix timestamp format, which means they are also integer numbers.

Variables

1. Date picker

Meaning: Provides a manual way to select and return a specific date.
Use Case: Useful if you want to compare against or calculate with a fixed date.
How it works: Select a date from a calendar interface.

2. Number input

Meaning: Allows you to input a fixed numeric value.
Use Case: Useful when you need a constant number for comparisons or calculations.
How it works: Enter the desired numeric value directly.

Mathematical Operators

1. Sum

Meaning: Adds together multiple numeric values or expressions.
Use Case: Useful for scoring systems or aggregating responses.
How it works: All selected values are summed and returned as one number.

2. Negation

Meaning: Multiplies a number by –1 to invert its sign.
Use Case: Useful when working with negative offsets or balancing scores.
How it works: The input value is returned as its negative equivalent.

Event properties

1. Get event payload value as number

Meaning: Extracts a value from an event payload and returns it as a number.
Use Case: Use when incoming event data needs to be used in numeric comparisons or calculations.
How it works: Enter the key of the event payload.

Study variables

1. Get study variable as integer

Meaning: Retrieves the value of a study variable and returns it as an integer.
Use Case: Ideal for numeric data like age, visit counts, thresholds, or scoring logic.
How it works: Provide the variable key.

2. Get study variable as float

Meaning: Retrieves the value of a study variable and returns it as a floating-point number.
Use Case: Use for precise numeric values such as weight, dosage, or percentages.
How it works: Provide the variable key.

3. Get study variable as date (POSIX seconds)

Meaning: Retrieves the value of a study variable and returns it as a date in POSIX seconds (Unix timestamp).
Use Case: Commonly used for scheduling survey availability, triggering automated messages, or recording time-based events like birthdate or visit date.
How it works: Provide the variable key.

Misc

1. Get timestamp

Meaning: Returns a timestamp based on the current date and time or a defined reference date.
Use Case: Useful for scheduling, comparing deadlines, or calculating relative dates (e.g., setting a reminder 7 days after survey submission).
How it works:
- Offset: Add or subtract time (e.g., +3 days, -2 weeks) from the reference point.
- Reference date: Define a custom date/time as the starting point. If none is provided, the current time is used.

2. Parse value as number

Meaning: Converts a given value (e.g., a flag or response value) into a numeric value.
Use Case: Helpful when participant input needs to be treated as a number for calculations or comparisons.
How it works: Enter the value to be parsed into a number.

Advanced

1. Use external service to evaluate event data (return float)

Meaning: Sends event data to an external service, which returns a floating-point number.
Use Case: Can be used for advanced calculations or evaluations that require external logic.
How it works: Select service name and route of the external event handler service.

2. Generate random number

Meaning: Produces a random number within a defined range.
Use Case: Useful for randomization tasks, such as assigning participants to different study groups.
How it works: Enter a minimum and maximum value. The expression will return a random number within this range.

3. Get current study counter value

Meaning: Retrieves the current value of a study-level counter.
Use Case: Use to display the current count or apply logic based on it.
How it works: Enter the counter scope key.

4. Increment and get study counter value

Meaning: Increases a study-level counter and retrieves the new value.
Use Case: Use to generate sequential values or trigger logic after incrementing.
How it works: Enter the counter scope key.

Date helpers

1. Get ISO week for timestamp

Meaning: Returns the ISO week number for a given timestamp.
Use Case: Helpful when rules depend on the calendar week (e.g., weekly schedules or reporting).
How it works: Provide a timestamp.

2. Get timestamp for next occurrence of an ISO week

Meaning: Calculates the timestamp for the next occurrence of a specified ISO week number.
Use Case: Useful for scheduling events or reminders based on calendar weeks.
How it works: Provide an ISO week number (e.g., 42), and the expression returns the timestamp for the start of that week in the current or next year.

3. Get timestamp for next occurrence of a start of month

Meaning: Returns the timestamp for the next start of a specified month.
Use Case: Ideal for monthly scheduling, e.g., sending out surveys at the beginning of each month.
How it works: Specify the month (e.g., March), and the expression calculates the timestamp for the next occurrence of the first day of that month.

Response Checkers

1. Get response value as number

Meaning: Extracts a numeric value from a participant’s response.
Use Case: Use when responses need to be evaluated numerically, e.g., for scoring or thresholds.
How it works: Enter the item key and the slot key of the response.

2. Count response items

Meaning: Counts the number of selected items in a multi-select or list-type response.
Use Case: Useful for determining how many options a participant selected.
How it works: Enter the item key and the slot key of the list response. The slot key refers to the response group that contains the list of selected item options whose count will be evaluated.

Participant State Checkers

1. Get study entry time

Meaning: Returns the timestamp marking the participant’s entry into the study.
Use Case: Useful for calculating durations, deadlines, or eligibility based on study entry.
How it works: No input required.

2. Get current study session's ID

Meaning: Returns the ID of the current study session.
Use Case: Use to store the session ID into a report data object, or compare with participant flags.
How it works: No input required.

3. Get survey key assigned from timestamp

Meaning: Retrieves the timestamp from which a specific survey was assigned to the participant.
Use Case: Useful for determining when a survey became available or tracking assignment history.
How it works: Enter the survey key.

4. Get survey key assigned until timestamp

Meaning: Retrieves the timestamp until which a specific survey remains assigned to the participant.
Use Case: Useful for checking survey availability windows or expiration.
How it works: Enter the survey key.

5. Get participant flag value as number

Meaning: Converts a participant flag value into a number.
Use Case: Useful for evaluating participant flags numerically, e.g., numerical comparison or progress tracking.
How it works: Provide the flag key.

6. Get last submission date

Meaning: Returns the timestamp of the participant’s most recent survey submission.
Use Case: Useful for tracking activity or triggering follow-ups.
How it works: Specify the survey key. The expression returns the timestamp of the last submission for that survey.

7. Get message next time

Meaning: Retrieves the next timestamp for when a specific message is scheduled to be sent.
Use Case: Useful for managing message timing, reminders, or notifications.
How it works: Enter the message key.

Incoming Participant State Checkers (Merge Events)

1. Get incoming study entry time

Meaning: Retrieves the study entry timestamp of the incoming (merged) participant.
Use Case: Useful for comparing entry times or preserving historical context during a merge.
How it works: No input required.

2. Get incoming survey key assigned from timestamp (Merge event)

Meaning: Returns the timestamp from which a specific survey was assigned to the incoming participant.
Use Case: Useful for tracking survey availability prior to a merge.
How it works: Enter the survey key.

3. Get incoming survey key assigned until timestamp (Merge event)

Meaning: Returns the timestamp until which a specific survey was assigned to the incoming participant.
Use Case: Useful for checking if a survey was still active at the time of merge.
How it works: Enter the survey key.

4. Get incoming last submission date (Merge event)

Meaning: Retrieves the timestamp of the last survey submission made by the incoming participant.
Use Case: Useful for evaluating recent activity before the merge.
How it works: Enter the survey key.

5. Get incoming message next time (Merge event)

Meaning: Returns the next scheduled time for a message assigned to the incoming participant.
Use Case: Useful for preserving message timing or rescheduling after a merge.
How it works: Enter the message key.

Strings

Some expressions return strings that can be used for various purposes, such as displaying messages or formatting output.

Variables

1. Text constant

Meaning: Allows you to input a fixed text value.
Use Case: Use to define labels or keys.
How it works: Enter the desired text directly.

Event properties

1. Get event payload as string

Meaning: Extracts a value from an event payload and returns it as a string.
Use Case: Use to inspect or process incoming event data.
How it works: Enter the key of the event payload.

Study variables

1. Get study variable as string

Meaning: Retrieves the value of a study variable and returns it as a string.
Use Case: Useful for workflows based on textual data such as participant group labels, phases of study flow, or other string-based values.
How it works: Provide the variable key.

Advanced

1. Use external service to evaluate event data

Meaning: Sends event data to an external service for evaluation, which returns a string.
Use Case: Use to validate or process data using external logic.
How it works: Select service name and route of the external event handler service.

Date helpers

1. Convert date to string

Meaning: Transforms a date value into a formatted string.
Use Case: Use to display dates in readable formats or pass them to external systems.
How It Works: Provide a date value and specify the desired format using placeholders. Examples:
- yyyy-MM-dd HH:mm:ss → "2023-12-25 14:30:45"
- MM/dd/yy hh:mm a → "12/25/23 02:30 PM"
- Supported Format Tokens:

Token	Description	Example
`yyyy`	4-digit year	`2006`
`yy`	2-digit year	`06`
`MM`	2-digit month	`01-12`
`M`	1-digit month	`1-12`
`dd`	2-digit day	`01-31`
`d`	1-digit day	`1-31`
`HH`	2-digit hour (24h)	`00-23`
`hh`	2-digit hour (12h)	`01-12`
`mm`	2-digit minute	`00-59`
`m`	1-digit minute	`0-59`
`ss`	2-digit second	`00-59`
`s`	1-digit second	`0-59`
`a`	AM/PM indicator	`AM`

Response Checkers

1. Get response value as string

Meaning: Retrieves a participant’s response as a string.
Use Case: Use to display or process responses in text format.
How it works: Enter the item key and the slot key of the response.

2. Get selected keys

Meaning: Retrieves the selected keys from a multi-select or list-type response as a comma-separated string.
Use Case: Useful for displaying or processing multiple selected options in a single string format.
How it works: Enter the item key and the slot key of the list response.

Participant State Checkers

1. Get participant flag value

Meaning: Returns the value of a specific participant flag as a string.
Use Case: Useful for displaying or using flag values in logic or communications.
How it works: Provide the flag key.

2. Get linking code

Meaning: Retrieves the linking code assigned to the participant.
Use Case: Use to connect data across studies or systems.
How it works: Enter the linking code or study code list key.

Incoming Participant State Checkers (Merge Events)

1. Get incoming participant flag value (Merge event)

Meaning: Returns the value of a specific participant flag from the incoming (merged) participant as a string.
Use Case: Use to transfer participant data between studies.
How it works: Provide the flag key.

2. Get incoming linking code value (Merge event)

Meaning: Retrieves the linking code assigned to the incoming (merged) participant.
Use Case: Use to maintain participant identity across merged studies.
How it works: Enter the linking code or study code list key.

Meaning: Executes one set of actions if a condition is true, and another set if it is false.
Use Case: Use when different outcomes should be triggered depending on whether a condition is met.
How it works: Define a condition. If it evaluates to true, the “then” actions are executed; otherwise, the “else” actions are triggered.

2. Conditional action set (IF-THEN)

Meaning: Executes a set of actions only if a specified condition is true.
Use Case: Use to trigger actions selectively based on participant data or study state.
How it works: Provide a condition. If it evaluates to true, the defined actions are executed. No actions are triggered if the condition is false.

3. Group of actions (DO)

Meaning: Executes multiple actions together as a single block.
Use Case: Use to organize and run several related actions in sequence.
How it works: Add all desired actions to the group. They will be executed in the order listed when the group is triggered.

General Study Actions

1. Update study status

Meaning: Changes the current status of the study for the participant.
Use Case: Use to reflect progress, transitions, or milestones in the study.
How it works: Select the new status value to assign.

2. Stop participation

Meaning: Ends the participant’s involvement in the study.
Use Case: Use when a participant should no longer continue, e.g., due to withdrawal or exclusion.
How it works: No input required. The participant is marked as no longer active in the study.

3. Finish participation

Meaning: Marks the participant’s study journey as complete.
Use Case: Use when all required tasks are done and the study is formally concluded.
How it works: No input required. The participant is marked as finished.

4. Start new study session

Meaning: Assigns a new study ID to the participant, starting a fresh session within the same study.
Use Case: Use when you want to group a new set of surveys or activities under a unique session for the participant.
How it works: No input required. A new, unique study ID is automatically generated.

5. Remove entry from study-wide code list

Meaning: Deletes a specific code entry associated with the participant from a global list.
Use Case: Use to revoke access, remove tags, or clean up data.
How it works: Provide the list key and the code to be removed.

6. Notify researchers (Email)

Meaning: Sends an email notification to designated researchers.
Use Case: Use to inform about events like e.g. consent withdrawal or survey completion.
How it works: Provide the message type and optional payload as key-value pair.

7. Reset study counter

Meaning: Sets a study-level counter back to zero.
Use Case: Use to restart counting for a new phase or time period.
How it works: Enter the scope key of the counter to reset.

8. Update study variable (boolean)

Meaning: Updates a study variable with a boolean value (true or false).
Use Case: Use for closing access to survey components if a threshold of maximal participants is reached.
How it works: Select the variable key and assign a boolean value.

9. Update study variable (string)

Meaning: Updates a study variable with a text value.
Use Case: Use to update the currently active study phase (e.g., from "phase1" to "phase2") if a threshold of participants is reached.
How it works: Select the variable key and assign a string value.

10. Update study variable (integer)

Meaning: Updates a study variable with a whole number.
Use Case: Use to track the number of participants meeting a certain condition (e.g., symptom reported or submitted a survey) or updating thresholds for triggering study-wide actions.
How it works: Select the variable key and assign an integer value.

11. Update study variable (float)

Meaning: Updates a study variable with a decimal number.
Use Case: Use to track study-wide calculated values from external services or update thresholds for continuous variables (e.g., maximum EM diameter)
How it works: Select the variable key and assign a float value.

12. Update study variable (date)

Meaning: Updates a study variable with a date value in POSIX seconds (Unix timestamp).
Use Case: Use to update the start or end date of survey availability when a defined participant threshold is reached.
How it works: Select the variable key and provide a date value in POSIX format.

Change Participant State

1. Update participant flag

Meaning: Sets or updates a flag value for the participant.
Use Case: Use to track states like eligibility, completion, or custom markers.
How it works: Provide the flag key and the value to assign.

2. Remove participant flag

Meaning: Deletes a specific flag from the participant’s record.
Use Case: Use to reset or clean up participant state markers.
How it works: Provide the flag key to be removed.

3. Add new survey

Meaning: Assigns a new survey to the participant.
Use Case: Use to trigger follow-up surveys or add new tasks.
How it works: Specify the survey key, and select a category (normal, priority, immediate, optional) to control its assignment type. Optionally, you can set “available from” and “available until” timestamps to define the survey’s availability window.

4. Remove all assigned surveys

Meaning: Deletes all surveys currently assigned to the participant.
Use Case: Use to reset the survey queue or clear outdated assignments.
How it works: No input required.

5. Remove one assigned survey

Meaning: Deletes a specific survey from the participant’s assignments.
Use Case: Use to cancel a particular survey without affecting others.
How it works: Provide the survey key to be removed and specify if the first or the last survey should be removed.

6. Remove all surveys of a specific key

Meaning: Deletes all surveys with a given key, regardless of assignment time.
Use Case: Use to remove repeated or recurring surveys of the same type.
How it works: Enter the survey key.

7. Send message now (immediately)

Meaning: Sends a message to the participant without delay.
Use Case: Use to deliver instant feedback or instructions.
How it works: Select the message to be sent immediately.

8. Schedule a message

Meaning: Plans a message to be sent to the participant at a future time.
Use Case: Use for reminders, notifications, or timed instructions.
How it works: Provide the message key and the scheduled timestamp.

9. Remove all scheduled messages

Meaning: Deletes all messages currently scheduled for the participant.
Use Case: Use to reset the message queue or cancel all pending notifications.
How it works: No input required.

10. Remove scheduled messages of a specific type

Meaning: Deletes scheduled messages that match a specific message key.
Use Case: Use to cancel a particular type of message without affecting others.
How it works: Enter the message key.

11. Set linking code

Meaning: Assigns a specific linking code to the participant.
Use Case: Use to establish connections between participants or datasets.
How it works: Select linking code key and enter the code as value.

12. Delete linking code

Meaning: Removes the currently assigned linking code from the participant.
Use Case: Use to break links or reset participant associations.
How it works: No input required. Specify optional keys if only linking code of these keys should be deleted.

13. Draw study code as linking code

Meaning: Uses the participant’s study code as their linking code.
Use Case: Use when the study code should serve as a unique identifier across systems.
How it works: Select the study code key. Specify optionally the linking code key to assign the study code to.

14. Remove confidential response by key

Meaning: Deletes a specific confidential response from the participant’s data.
Use Case: Use to remove sensitive information selectively.
How it works: Provide the response key to be removed.

15. Remove all confidential responses

Meaning: Deletes all confidential responses associated with the participant.
Use Case: Use to fully clear sensitive data.
How it works: No input required.

16. Increment and store study counter as flag

Meaning: Increases a study-level counter and saves the value as part of a participant flag.
Use Case: Use to assign sequential IDs or track event counts.
How it works: Enter the counter scope key and the flag key. Optionally, define a prefix to prepend to the value and padding to ensure a minimum number of digits (e.g., ST-0005).

17. Increment and store study counter as linking code

Meaning: Increases a study-level counter and stores the result as part of a linking code for the participant.
Use Case: Use to generate unique codes for linking data across systems or studies.
How it works: Enter the counter scope key and the linking code key. Optionally, define a prefix to prepend to the code and padding to ensure a minimum number of digits (e.g., LC-0007).

18. External event handler

Meaning: Triggers an external event or integration.
Use Case: Use to connect with external systems or services.
How it works: Provide the service name and route.

19. Initialize report

Meaning: Starts a new report for the participant.
Use Case: Use to begin tracking or compiling summarized participant data.
How it works: Specify the report key.

20. Cancel report

Meaning: Cancels an active report for the participant for the current event.
Use Case: Use to stop and discard reports.
How it works: Provide the report key to cancel.

21. Update report data

Meaning: Modifies or adds data to an existing report.
Use Case: Use to keep reports current or add new findings.
How it works: Specify the report key and the attribute you want to update. Enter the new value for the attribute. Optionally, you can select how the value should be interpreted (e.g., as a date, float, integer, raw message, or list of keys).

22. Remove report data by attribute key

Meaning: Deletes specific data from a report based on the attribute key.
Use Case: Use to selectively remove report entries without canceling the entire report.
How it works: Provide the report key and the attribute to be removed from the report.

Methods of the study engine

On this page