Translations:Advanced Field Epi:Manual 1 - Disease Investigation/342/en

One of the best protections against confounding bias is randomisation. Randomisation assures that, on average, most confounders will be distributed roughly evenly between treatment groups or sub-samples. The reason randomisation is useful is that randomisation is the only available method for controlling confounding due to unknown or unmeasured variables. All other methods to control confounding assume that you know enough to have a measurement of the potential confounder. These other methods for controlling confounding include: