A NOTE ON THE RULE FOR SEQUENTIAL SELECTION

An extension of the sequential selection problem of Kwan and Yuan whic h is shown to be equivalent to a simple search problem is solved. In t heir model, candidates for a single job position are screened until on e of them is accepted. An alternative proof technique, suggested by us and independently by Chun and Platt in 1992, is used to show that the Kwan-Yuan rule for sequential selection is optimal not only for their case but also for the general problem of multiple positions for m non -identical jobs. This rule, however, is not necessarily optimal when a cost of delay is incurred (instead of cost of information). Furthermo re, the equivalence between the simplest search model discussed in 196 2 by Blackwell and others and the sequential selection problem of Kwan and Yuan is shown. Finally, a counter example demonstrates that, for the cost of delay case, a pairwise interchange process may lead to a l ocal extremum.