Variable Properties
For each variable, you can specify different properties and provide a short text description of what the variable is used for. Name and Data Type are mandatory. Format is also important to specify when using arrays or data frames. All other properties are optional or fixed depending on the data type.
Name
The name is used as a handle for the variable in events, objects, when copying tasks, and in the data view. Names must be unique across the study: two variables cannot share the same name. The name can be changed on all variables except System Variables.
Accepted values: any ASCII string. Do not use periods (.).
Data Type
The data type determines what kind of values the variable can hold and what operations can be applied to it.
| Data Type | Description |
|---|---|
String | Any text, including numbers and special characters. |
Numeric | Numeric values only. |
Boolean | true or false only. |
Categorical | A fixed set of predefined levels. Mostly used for factor variables. |
Date | Date values in yyyy/mm/dd format. |
Time | Time values in hours/minutes/seconds format. |
File | Image, video, or audio file data. |
Scale
The scale determines the level of measurement. Useful for numeric variables and may be used by future analysis features.
| Scale | Description |
|---|---|
Undefined | No selection. |
Nominal | Categories with no inherent order. |
Ordinal | Ranked values with no consistent interval. |
Interval | Values with consistent intervals but no true zero (e.g. temperature). |
Ratio | Values with consistent intervals and a true zero (e.g. weight). |
Format
The format determines whether the variable holds a single value or a collection of values.
| Format | Description |
|---|---|
Scalar | A single value. |
Array | An ordered list of values. |
Data Frame | Multiple variables nested in a CSV structure, where each column is a variable. |
Start Value
The start value is the default value the variable resets to at the start of each trial (if Reset at Trial Start is enabled). It can also be used to permanently store content such as text, images, video, or audio.
For array variables, the start value can be a complete array. You can upload a CSV file or add entries manually.
Reset at Trial Start
When enabled, the variable resets to its start value at the beginning of each new trial. Enable this for variables that record per-trial data like responses or reaction times. Disable it for variables that accumulate across trials, such as scores or persistent data arrays.
Record Variable
When enabled, the variable value is recorded and saved at the end of each trial. Recording is enabled by default for system, factor, and object variables.
Record Type
Determines how value changes are recorded during a trial.
| Option | Description |
|---|---|
All changes / time series | Records every value change during the trial, each with a timestamp. See Time Series Variables for sampling method options. |
Final value only | Records only the value at the end of the trial. |
Further reading
Time Series Variables
How to set up the Sampling method and Record Type for continuous measurements like mouse tracking and physiological signals.
Variables Tab
The global variable list where you can view, create, edit, and delete all variables in your study.
Working with Variables
The hub page for the working-with-variables section: types, properties, recording options, and data frames.