What level of evidence do cohort studies belong to according to evidence-based medicine?

Evidence-based medicine level of evidence cohort studies are classified as level 3 evidence.

Evidence-based medicine (EBM) means "evidence-based medicine" and is also known as empirical medicine. The core idea is that medical decisions should be made on the basis of the best available clinical research, while also emphasizing the incorporation of personal clinical experience.

Evidence-based medicine was developed to overcome the shortcomings of traditional medicine, which was based on empirical medicine, i.e., diagnosing and treating patients on the basis of non-experimental clinical experience, clinical data, and an understanding of the basics of disease. Evidence-based medicine is not a substitute for clinical skills, clinical experience, clinical data and medical expertise, but only emphasizes that any medical decision should be based on the best scientific research evidence.

On the description of evidence-based medicine, a recurring term is evidence, the so-called evidence-based is to follow the evidence of the meaning, because this concept comes from the translation of the English Evidence-based, where the evidence Evidence is the core of the problem. So evidence-based medicine evidence is mainly said to be clinical research evidence. So what exactly is clinical research evidence?

There is a hierarchy of clinical research evidence in evidence-based medicine:

Level 1: A systematic evaluation or meta-analysis of all randomized controlled trials of good quality and reliability for a specific treatment for a specific disease.

Level II: Randomized controlled trials with adequate individual sample sizes.

Third level: studies with a control group but not using randomized groups.

Level IV: A series of case observations without controls.

Grade V: Expert opinion.