collection of material block NCIt:C86947 NCIt:C25436 NCIt:C48949 NCIt:C61286 James Malone A block or batch is an experimental unit arrangement into a group which is similar to one another. Typically, a blocking factor is a source of variability that is not of primary interest to the experimenter. An example of a blocking factor might be the sex of a patient; by blocking on sex, this source of variability is controlled for, thus leading to greater accuracy. batch