definitive screening design

**Definitive Screening Design (DSD)** is a **three-level screening design that can simultaneously estimate main effects, quadratic effects, and some two-factor interactions** — introduced by Jones and Nachtsheim (2011), DSDs overcome the limitations of traditional 2-level screening designs. **DSD Advantages** - **Three Levels**: Includes center points for each factor, allowing detection of curvature. - **Structure**: $2k+1$ runs for $k$ factors (e.g., 13 runs for 6 factors). - **Model Building**: With ≥6 factors, DSDs can estimate a full quadratic model in active factors. - **No Confounding**: Main effects are completely unconfounded with two-factor interactions. **Why It Matters** - **Screen + Model**: Combines screening and response surface modeling in a single design — saves an experimental round. - **Curvature Detection**: Unlike Plackett-Burman, DSDs detect non-linear effects that indicate you are near an optimum. - **Modern Standard**: Rapidly becoming the preferred screening design in practice (available in JMP, Minitab). **DSD** is **screening and optimization in one shot** — a modern design that identifies important factors AND models their effects simultaneously.