The difference is always pre-existing no matter what the condition is
Evaluation for quasi: If it is set in controlled conditions, then evaluate using lab or if it is set in a realistic environment, evaluate using field
There is only one exception for the quasi evaluation: there is no Iv being manipulated, for example, lab and field conditions would need to create high stress and ow stress but quasi allow a more gentle process for selecting such as asking for stress levels and allocating into correct conditions
What is the independent variable (IV) in natural experiments?