The questions you ask also need to be formatted in such a way as to aid you in your search for answers – see the ACQUIRE section of this resource for more details. A well-formed clinical question is the most efficient route to obtaining a clear answer.
Certain study types (e.g. randomised controlled trials, cohort studies, case-control studies, cross-sectional studies and the like) are specifically designed to answer, and are therefore better at answering, certain types of clinical questions (e.g. those addressing treatment, risk, or prevalence). We will only briefly identify and categorise the main study types below; more details can be found in APPRAISE.
Clinical questions can be divided into five main topic areas: Questions that relate to 1) treatment, 2) prognosis and incidence, 3) aetiology or risk, 4) diagnosis, and 5) prevalence. We will cover these in turn below.
Treatment – These types of questions refer to treatment choices a veterinarian would need to make in order to achieve a desirable outcome. These choices can include drugs or medicines to be used, surgical methods, changes in diet or management, and many more. These types of questions are best answered by randomised controlled trials when they are available.
Prognosis and Incidence – These types of questions relate to the likelihood of disease or the progression of disease over time. These questions are best answered by cohort studies.
Aetiology and Risk – These types of questions investigate the origin of disease or the factors influencing development of a certain condition or disease. These questions are best answered by cohort studies, case-control studies or cross-sectional studies.
Diagnosis – These types of questions involve identification of a disorder based on the animal’s presenting signs. These questions are best answered by diagnostic test validation studies (also known as diagnostic evaluation studies).
Prevalence – These questions consider the frequency of disease at a certain point in time, and are best answered by cross-sectional studies and surveys.
Categorising your clinical questions in this way can help you to decide which study design would best answer your question. In the APPRAISE and ASSESS chapters, we will look further at the different levels of evidence and the study types commonly used in veterinary medicine.