(o,opop,e, refo) ≡ s-compellingness(o, e, refo)>µ x +kσ x , where − o, e, and refo are defined as in the previous Def; opop is an objective population (e.g., siblings(o)), and opop>2 − p∈ opop; x∈X = s-compellingness(p, e, refo) − µ x is the mean of X, σ x is the standard deviation and k is a user-defined constant Similar measures for the comparison of two entities are defined and extensively discussed in (Klein 1994).
by setting the constant k to different values, it is possible to control in a principled way how many objectives (i.e., pieces of evidence) are included in an argument, thus controlling the degree of conciseness of the generated arguments.