Q

Quality
A vague notion of the methodological strength of a study, usually indicating the extent of bias prevention.

Quasi-random allocation
Methods of allocating people to a trial that are not random, but were intended to produce similar groups when used to allocate participants. Quasi-random methods include: allocation by the person's date of birth, by the day of the week or month of the year, by a person's medical record number, or just allocating every alternate person. In practice, these methods of allocation are relatively easy to manipulate, introducing selection bias. See also random allocation, randomisation.