Two subtypes of non-experimental studies exist:
- descriptive studies and
- analytic studies.
Descriptive (or exploratory) studies do not try to explain a theory; for example, they just describe frequencies of the phenomenon (payment fraud).
Examples of descriptive studies are the Nilson Report, which publishes news and statistics about the card and mobile payment industry and the Observatory for Payment Card Security (OSCP) of the Banque de France.
In contrast, analytic studies attempt to test hypotheses and provide explanations about the phenomenon.
Examples of analytic studies are those in which relationships between the exposure, e.g., fraud, and the outcomes, e.g., the payment method, such as Visa, MasterCard, and PayPal, are searched for.