An empirical model that cannot be implemented in practice. Experimental psychologists use it as a standard.

It includes three criteria:

1. Idealized experiment (only the independent and dependent variables change and are not affected by external or additional variables).

2. Endless experiment (the experiment must continue indefinitely. as there is always the possibility that a previously unknown factor may emerge).

3. تجربة الانسجام الكامل (يجب أن يكون الوضع التجريبي مطابقًا تمامًا لكيفية حدوثه “في الواقع”).