Time-trend free run orders with the minimum level changes

Abstract

Time trend free run orders of factorial designs with the minimum number of level changes are very desirable in many applications. In this paper, a new construction technique is discovered to provide linear trend free run orders of sn factorial designs with the minimum number of level changes for all even positive integers s. Furthermore, when s is an odd positive integer, a run order of sn is constructed which has the minimum number of level changes, and whose time count does not increase along with n.