group randomization restricted randomization Adapted from Wikipedia: https://en.wikipedia.org/wiki/Restricted_randomization last accessed: 2016/12/15 Alejandra Gonzalez-Beltran Orlaith Burke Philippe Rocca-Serra Restricted randomization is a kind of randomization which is used or occured when hard to change factors exist in a study design. In other words, when complete randomization is not possible, a case of restricted randomization exists, for instance in the case of split-plot design. Restricted randomization allows intuitively poor allocations of treatments to experimental units to be avoided, while retaining the theoretical benefits of randomization. Restricted randomization can also result from an unplanned event and is then something that should be avoided. RandomizeR R package can be used to detect such events and assess the quality of randomization process. complete randomization metadata complete