Resolution of a fractional factorial design
= Resolution of a fractional factorial design
{title2=$R=\min_{G\in\mathcal H\setminus\{I\}}|G|$}
The resolution of a regular fraction is the shortest nonidentity word in its <defining contrast subgroup>. Two effects alias only when their word product belongs to that subgroup. Thus resolution VI separates all <main effects> and <two-factor interactions> from one another and from three-factor interactions, though some three-factor interactions alias in complementary pairs.