Bradford Hill criteria

The Bradford Hill criteria is a way to decide if something causes something else. For example, scientists might use the Bradford Hill criteria to decide if eating broccoli causes a person to be healthy.

It works by having nine different rules. All nine have to be true for it to be true that eating broccoli causes a person to be healthy.

The first rule is called the strength of association. This means that the stronger the link between eating broccoli and being healthy, the more likely it is true.

The second rule is called consistency. This means that different scientists have to get the same results when they look at the same kind of data.

The third rule is called specificity. This means that eating broccoli has to be linked with being healthy, but it can't be linked with anything else.

The fourth rule is called temporality. This means that eating broccoli has to come before being healthy.

The fifth rule is called biological gradient. This means the more broccoli you eat, the healthier you should be.

The sixth rule is called plausibility. This means that there needs to be a scientific reason for why eating broccoli causes you to be healthy.

The seventh rule is called coherence. This means that it needs to make sense with what we already know to be true.

The eighth rule is called experiment. This means that scientists need to do an experiment to try to show that eating broccoli causes you to be healthy.

The ninth rule is called analogy. This means that eating broccoli should be linked to something that we already know causes something else, like smoking causes cancer.

If all nine of the rules are true, then it is likely that eating broccoli causes a person to be healthy.