realized in realizable entity group assignment based on blocking variable specification blocking variable https://onlinecourses.science.psu.edu/stat503/node/18 Orlaith Burke a blocking variable is a independent variable which is used in a blocking process part of an experiment with the purpose of maximizing the signal coming from the main variable. https://onlinecourses.science.psu.edu/stat503/node/19 Often in medical studies, the blocking factor used is the type of institution. This provides a very useful blocking factor, hopefully removing institutionally related factors such as size of the institution, types of populations served, hospitals versus clinics, etc., that would influence the overall results of the experiment. nuisance variable Alejandra Gonzalez-Beltran Philippe Rocca-Serra variable ready for release