A controlled environment manages or removes as many variables as possible so differences can be attributed more confidently to the independent variable. In an experiment, this supports causal questions such as whether a change produces a measurable outcome. section 3.2.3
Website button test
An A/B test might change only a website button’s color and compare newsletter subscription rates across groups. When color is the only difference, higher subscriptions can be attributed more confidently to the changed button color. section 3.2.3
A controlled environment works alongside other experimental safeguards:
- Select participants randomly when possible. section 3.2.3
- Assign participants randomly to treatment and control groups. section 3.2.3
- Manipulate an independent variable directly and measure the resulting outcome. section 3.2.3
