Dalle Grave

Here’s a quick tip: when a study that purports to find evidence of treatment effectiveness–preliminary or not–doesn’t have a control group (a group that doesn’t undergo treatment but is otherwise similar to the group that does), you should raise your eyebrows. Or shake your head. Or roll your eyes. Whichever you prefer.

Why do we need a control group? If the treatment works, we will see improvement in the patients, so isn’t that evidence enough? Well, no.

[T]he whole idea of an experiment is to identify two identical groups of people and then to manipulate something. One group gets an experimental treatment, and one does not. If the group that gets the treatment (e.g., a drug, exposure to a violent video game) behaves differently than the control group that did not get the treatment, we can attribute the difference to the treatment – but only if we can rest assured