The pyramid of evidence in science: Different types of studies under the magnifying glass echo

Basis Scientific communication It is knowing how to analyze and understand the different studies we encounter on a daily basis. For this, one of the key points is to know each type of study in order to immediately determine its potential scope and impact. Will this study be considered a future reference or will it add stone to the building? Does science advance or are they just stories?

Follow this guide prepared by our science communication team to understand all the ins and outs of the different papers.

A quick overview of the different studies

A picture is worth a thousand words, look at it Evidence pyramid below.

The higher the levels of the pyramid, the more studies with a high degree of evidence. This means that those at the top are more likely to achieve consensus in an area than those at the bottom.

But each type of study has its strengths and weaknesses. Let’s see which ones.

Anecdotes, expert thoughts and case studies (Floors 1 and 2 of the pyramid).

Although they may appear anecdotal, the scientific accounts presented in these studies enrich the existing literature and offer reflective perspectives. It has no evidentiary value but is sometimes the starting point for further research.

Observational studies (floors 3, 4 and 5 of the pyramid).

These studies are observational Show links. They provide an overview of a topic but cannot prove a causal relationship because they do not follow an empirical method. These studies can be done on a large scale, which makes them less accurate on an individual level. However, they are very useful for identifying trends and directing researchers towards more in-depth studies.

It is often the goal of observational studies Discover factors related to health events (diseases, injuries, etc.). And even if one study isn’t enough to prove something, several studies that come to the same conclusions can catch the attention of researchers. They tell themselves there is something to dig into and this can be the starting point for future trials.

exist Three types of observational studies : cohort studies that follow a group of people over a period of time, case-control studies that compare two groups of people in a given situation and comparative cross-sectional studies that study a group of people in particular (those who often suffer from migraines for example) to see if They had common characteristics.

Randomized controlled studies (6th floor of the pyramid).

Randomized controlled studies are part of empirical research. Researchers study an idea and develop a treatment or protocol to test it. In these studies, some participants receive the treatment and others do not, but without knowing it (they are given a placebo instead).

If the scientists themselves in a randomized study do not know who is taking what at the moment T, we say that this study was conducted at double blind. Rest assured, at the time of analysis, researchers work with accurate data and leave nothing to chance. They just made sure, thanks to the various members of their team, to distort their study as little as possible.

The study protocols are randomized, double-blind to provide the most reliable results. But be careful not to get too easily convinced by these kinds of studies. Their value is highly dependent on the protocols used and the interpretation of the results.

👉🏼 Meta-analytics and summary review (top floor of the pyramid).

These studies collect data from dozens or hundreds of experimental or observational studies. they consider Research references. Often their weak point is the selection authors make of the studies that appear in their composition. A good meta-analysis should include all the important studies on a topic, even if they contradict each other.

Another type of knowledge synthesis is called “Position Stands”. They are developed by respected organizations and provide practical advice and guidance in areas such as nutrition, physical activity, etc.

Qualitative studies.

They are not included in the pyramid because they focus on the human side of things. The data collected is not the same as that used in quantitative studies because it is more subjective. For example: “How do you feel about it?” or “Was Device X easy to use?”

These studies complement quantitative studies and help researchers understand the findings in context. When a study uses both qualitative and quantitative methods, it is said to be using a mixed method.

Our teamkeen on popularizing science for the general public, remains at your disposal if you have any questions.