${c}_{i}$ is a numeric flag indicating the contrast used in the case of a categorical variable. With
${c}_{i}=0$ indicating that dummy variables were used for variable
${v}_{i}$ in this term. The remaining six types of contrast; treatment contrasts (with respect to the first and last levels), sum contrasts (with respect to the first and last levels), Helmert contrasts and polynomial contrasts, as described in
g22ycf, are identified by the integers one to six respectively.