TY - JOUR
T1 - Definitive screening designs with added two-level categorical factors
AU - Jones, Bradley
AU - Nachtsheim, Christopher J.
PY - 2013/4
Y1 - 2013/4
N2 - Recently, Jones and Nachtsheim (2011) proposed a new class of designs called definitive screening designs (DSDs). These designs have three levels, provide estimates of main effects that are unbiased by any second-order effect, require only one more than twice as many runs as there are factors, and avoid confounding of any pair of second-order effects. For designs having six factors or more, these designs project to efficient response surface designs with three or fewer factors. A limitation of these designs is that all factors must be quantitative. In this paper, we develop column-augmented DSDs that can accommodate any number of two-level qualitative factors using two methods. The DSD-augment method provides highly efficient designs that are still definitive in the sense that the estimates of all main effects continue to be unbiased by any active second-order effects. An alternative procedure, the ORTH-augment approach, leads to designs that are orthogonal linear main effects plans; however, some partial aliasing between main effects and interactions involving the categorical factors is present.
AB - Recently, Jones and Nachtsheim (2011) proposed a new class of designs called definitive screening designs (DSDs). These designs have three levels, provide estimates of main effects that are unbiased by any second-order effect, require only one more than twice as many runs as there are factors, and avoid confounding of any pair of second-order effects. For designs having six factors or more, these designs project to efficient response surface designs with three or fewer factors. A limitation of these designs is that all factors must be quantitative. In this paper, we develop column-augmented DSDs that can accommodate any number of two-level qualitative factors using two methods. The DSD-augment method provides highly efficient designs that are still definitive in the sense that the estimates of all main effects continue to be unbiased by any active second-order effects. An alternative procedure, the ORTH-augment approach, leads to designs that are orthogonal linear main effects plans; however, some partial aliasing between main effects and interactions involving the categorical factors is present.
KW - Alias
KW - Conference matrix
KW - Confounding
KW - Coordinate exchange algorithm
KW - D-efficiency
KW - Robust designs
KW - Screening designs
UR - http://www.scopus.com/inward/record.url?scp=84878967576&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84878967576&partnerID=8YFLogxK
U2 - 10.1080/00224065.2013.11917921
DO - 10.1080/00224065.2013.11917921
M3 - Article
AN - SCOPUS:84878967576
SN - 0022-4065
VL - 45
SP - 121
EP - 129
JO - Journal of Quality Technology
JF - Journal of Quality Technology
IS - 2
ER -