Describe the seven “levels of evidence” and provide an example of the type of practice change that could result from each.

Describe the seven “levels of evidence” and provide an example of the type of practice change that could result from each.

ANSWER
The seven levels of evidence are a framework for evaluating the strength of evidence supporting a particular practice change. The levels are ranked from lowest to highest, with Level 1 being the strongest and Level 7 being the weakest.

Level 1: Meta-analysis of randomized controlled trials (RCTs)

A meta-analysis is a study that combines the results of multiple RCTs. RCTs are the gold standard of research, as they randomly assign participants to either an intervention or a control group, which helps to control for confounding variables. A meta-analysis of RCTs provides the strongest evidence for a practice change.

Example practice change: Implementing a new medication regimen for the treatment of hypertension.

Level 2: Individual randomized controlled trials (RCTs)

An RCT is a study that randomly assigns participants to either an intervention or a control group. This helps to control for confounding variables and allows researchers to make causal inferences about the effects of the intervention.

Example practice change: Implementing a new surgical technique for the treatment of a particular condition.

Level 3: Non-randomized controlled trials (NRCTs)

An NRCT is a study that does not randomly assign participants to either an intervention or a control group. This means that the results of NRCTs are less reliable than those of RCTs, as they may be subject to confounding variables.

Example practice change: Implementing a new educational program for nurses on the care of patients with diabetes.

Level 4: Case-control studies

A case-control study is a study that compares two groups of people: those who have a particular condition (cases) and those who do not (controls). The researchers then look for factors that are more common in the cases than in the controls, which may be risk factors for the condition.

Example practice change: Implementing a new screening program for a particular cancer.

Level 5: Cohort studies

A cohort study is a study that follows a group of people over time to see who develops a particular condition. The researchers then look for factors that are associated with the development of the condition.

Example practice change: Implementing a new intervention to prevent a particular disease.

Level 6: Qualitative studies

Qualitative studies are studies that use non-numerical data, such as interviews, observations, or focus groups. These studies can provide insights into the experiences of people with a particular condition or the implementation of a particular intervention.

Example practice change: Implementing a new patient education program.

Level 7: Expert opinion

Expert opinion is the lowest level of evidence. It is based on the opinions of experts in the field, but it is not based on any empirical research.

Example practice change: Implementing a new policy based on the recommendations of a panel of experts.

It is important to note that the level of evidence required to support a practice change will vary depending on the context. For example, a stronger level of evidence may be required to support a practice change that is costly or invasive than a practice change that is simple and inexpensive.

References:

Centre for Evidence-Based Medicine. (2023). Levels of Evidence.

The National Institute for Health and Care Excellence. (2020). Grading the Recommendations.