Manipulated variable refers to variables in an experiment or testing environment where a variable is manipulated to test for a change in outcomes. Manipulated variables are used in many different scenarios, including computer programming, system testing and drug testing.
In computer programming, variables are manipulated by using functions and commands. Addition, subtraction and testing for a value are all types of variable manipulation. You may also manipulate variables when debugging the application to test your error handling or outcomes.
The best example of manipulated variable testing is the use of placebos in drug testing. When measuring the rate of a patient's recovery, the main variable is the medication that is being tested. The variable is manipulated between the patient taking the tested medication, a placebo or an alternative treatment.