This article studies the issue of choosing optimal designs of regular s^n-p fractional factorial designs when both blocking and foldover techniques are simultaneously employed, here s is a prime or prime power. Based on a general decomposition structure, the treatment and block split word length patterns of the combined blocked design under a general foldover plan are defined. They are proved to be independent of the choice of the block foldover plans. It is also shown that, for an initial unblocked design, a pair of blocking and foldover plans has minimum aberration for the combined blocked d...
