Bit pattern

is the way in which a term in a statistical model is stored within Genstat. Each term is stored in one or more integers, and there is a “bit” in the integer(s) for each of the factors in the model. (The bits correspond to the powers of 2: 1, 2, 4 etc.) The corresponding bit is set for each of the factors in the model term. So the number 5 (= 1 + 4) represents a model term containing the first and third factors.