Optimal foldover plans for two-level nonregular orthogonal designs

William Li, Dennis K.J. Lin, Kenny Q. Ye

Research output: Contribution to specialist publicationArticle

64 Scopus citations


This article considers optimal foldover plans for nonregular designs. By using the indicator function, we define words with fractional lengths. The extended word-length pattern is then used to select among non-regular foldover designs. Some general properties of foldover designs are obtained using the indicator function. We prove that the full-foldover plan that reverses the signs of all factors is optimal for all-run and 20-run orthogonal designs. The optimal foldover plans for all 16-run (regular and nonregular) orthogonal designs are constructed and tabulated for practical use. Optimal foldover plans for higher-order orthogonal designs can be constructed in a similar manner.

Original languageEnglish (US)
Number of pages5
Specialist publicationTechnometrics
StatePublished - Nov 2003
Externally publishedYes


  • Extended word length pattern
  • Foldover design
  • Generalized resolution
  • Indicator function
  • Orthogonal design

ASJC Scopus subject areas

  • Statistics and Probability
  • Modeling and Simulation
  • Applied Mathematics


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