Iranian Statistical Society Journal of the Iranian Statistical Society 1726-4057 24 1 2025 06 01 Evaluation of Second-Order Response Designs with Errors in Factor Levels in the Cuboidal Region 157 169 732362 10.22034/jirss.2025.2049136.1090 EN Ifeoma Ogochukwu Ude Department of Statistics, University of Nigeria, Nsukka, Enugu State, Nigeria. 0009-0003-9841-1122 Abimibola Victoria Oladugba Department of Statistics, University of Nigeria, Nsukka, Enugu State, Nigeria. Amarachi Favour Didiugwu Department of Statistics, University of Nigeria, Nsukka, Enugu State, Nigeria. Lilian Ifeoma Nnanna Department of Statistics, University of Nigeria, Nsukka, Enugu State, Nigeria. Department of Statistics, University of Regina, Regina, Canada. Journal Article 2024 12 28 Errors in factor levels often occur in response surface modeling. A design in which these errors have minimal effect is the desired design. <span class="fontstyle0">This study evaluates the prediction capability of second-order Orthogonal Array Composite Design (OACD) and Orthogonal Uniform Composite Design (OUCD) with and without errors in factor levels for</span> 3 ≤ k ≤ 5 factors using 2, 3, and 5 center points in the cuboidal region. Design optimality criteria (in terms of G- and IV-optimality values) and quantile dispersion plots are used to examine the prediction capability of these designs. The results show that OUCD is the preferred design in terms of G-optimality, while IV-optimality and quantile plots indicate that OACD is the preferred design in both the presence and absence of errors in factor levels. https://jirss.irstat.ir/article_732362_ea90131db44cc96d2977f81dac46bf60.pdf