Primary Source vs. Secondary Source
Empirical Research (Primary Source): Studies that are based on observations or experiments. Clinical trials, case studies, and meta-analyses are typical empirical research.
Literature Review (Secondary Source): Articles that summarize the research on a particular topic. They often include a summary, a systematic review, and meta-analyses.
Case Study (Primary Source): Articles that provide real cases from clinical practice. They often include descriptions of symptoms, diagnosis, and treatment.
Clinical Trial (Primary Source): Studies that are often based on large cohorts of people. They typically include descriptions of methodology and control groups.
Position Paper (Secondary Source): Papers of opinions that reflect personal thoughts, or institutional beliefs, or a conclusion based on facts. Their typical goal is to persuade or influence the reader.
Book Review (Secondary Source): Papers of opinions that critique recent publications in the field. They tend to be brief and to the point.
UCLA Library Wheel of Sources by Kian Ravaei & Jen Pierre
Evidence-Based Research Questions
Your question needs to identify the key problem, what treatments/tests are you preparing for the patient, what alternative treatments (if any) are being considered, and what is the desired outcome to promote or avoid.
P = Problem: How do you describe a group of patients similar to yours? What are the most important characteristics of the patient? This may include the primary problem, disease, or co-existing conditions. Sometimes the gender, age or race of a patient might be relevant to the diagnosis or treatment of a disease.
I = Intervention: Which main intervention, prognostic factor, or exposure are you considering? What do you want to do for the patient? Prescribe a drug? Order a test? Order surgery? Or what factor may influence the prognosis of the patient - age, co-existing problems, or previous exposure?
C = Comparison: What is the main alternative to compare with the intervention? Are you trying to decide between two drugs, a drug and no medication or placebo, or two diagnostic tests? Your clinical question may not always have a specific comparison.
O = Outcome: What do you hope to accomplish, measure, improve or affect? What are you doing for the patient? Relieve or eliminate the symptoms? Reduce the adverse events? Improve function or test scores?