Column-orthogonal strong orthogonal arrays of strength two plus and three minus

Summary Strong orthogonal arrays have better space-filling properties than ordinary orthogonal arrays for computer experiments. We consider column-orthogonal strong orthogonal arrays of strength two plus and three minus, and present methods of constructing such designs. Several situations are examined, including those of four or higher levels and mixed levels. The methods are based on both regular and nonregular designs. The resulting designs inherit the good property of strong orthogonal arrays of strength two plus or three and have the additional property of column orthogonality. This type of design is a better choice for computer experiments.