AbstractFractional factorial designs are among the most important statistical contributions to the efficient exploration of the effects of several controllable factors on a response of interest. Fractional factorials are widely used in experiments in fields as diverse as agriculture, industry, and medical research. A key feature of fractional factorials that is not shared by more ad hoc methods for reducing the size of experiments is that the statistical properties are known in advance of experimentation. Consequently, an experimenter can investigate alternatives that enable the goals of the experiment to be met with the least cost, shortest time, or most effective use of resources. On occasion, an experimenter might decide not to conduct an experiment as originally planned once the statistical properties of the design are known. This article highlights the fundamental concepts, design strategies, and statistical properties of fractional factorial designs. Copyright © 2009 John Wiley & Sons, Inc.This article is categorized under: Statistical Models > Linear Models Statistical Models > Classification Models