What does experimental epidemiology begin with?

Experimental epidemiology starts with a hypothesis about a particular disease because this hypothesis serves as the foundational question or statement that the researcher seeks to test through experimentation. The hypothesis is derived from observations, previous research, or theoretical frameworks regarding how a disease may be caused or affected by various factors.

This initial hypothesis guides the design of the study, including how researchers will collect data, what variables to manipulate, and how to assess outcomes. Once a solid hypothesis is in place, researchers can then develop a structured experiment to explore its validity, ultimately contributing to the understanding of disease causation and prevention.

The other choices represent steps that may be part of the broader research process. While literature reviews or preliminary survey results may assist in formulating a hypothesis, they do not initiate the experimental approach itself. Similarly, random selection of participants is a part of designing the experiment but follows the establishment of a hypothesis. The core of experimental epidemiology is that it is hypothesis-driven, focusing specifically on establishing a causal relationship through controlled studies.