# Define an independent variable

Aim

To label trials, arenas and subjects using an independent variable, for example the level of the treatment, the ID of the subjects and the day of testing.

Procedure

1.Open the Trial List.

2.Click the Add Variable button.

A new column with label User-defined is inserted at the end of the table.

3.Specify the label (name), description, type, format, predefined values and scope of the variable. See below an example of a Trial List with two independent variables, Rat ID and Treatment.