Selecting significant effects in factorial designs: Lenth's method versus using negligible interactions

Significant drug interactions in dermatology

Systemic drugs have been used widely in the treatment of many skin diseases. Although dermatologists are familiar with the guidelines of selecting appropriate patients and prescribing systemic drugs, their knowledge about the side effects and significant interactions of systemic drugs used in dermatology is more limited. So a short review on important drug interactions seems to be useful. Some ...

Developing multicomponent interventions using fractional factorial designs.

Multicomponent interventions composed of behavioral, delivery, or implementation factors in addition to medications are becoming increasingly common in health sciences. A natural experimental approach to developing and refining such multicomponent interventions is to start with a large number of potential components and screen out the least active ones. Factorial designs can be used efficiently...

Testing Multiple Dispersion Effects in Unreplicated Fractional Factorial Designs

In unreplicated 2kp designs, the assumption of constant variance is commonly made. When the variance of the response differs between the two levels of a column in the effect matrix, that column produces a dispersion effect. In this article we show that two active dispersion effects may create a spurious dispersion effect in their interaction column. Most existing methods for dispersion-effect t...

Model-Robust Factorial Designs

Multistratum Fractional Factorial Designs

Recent work on multistratum fractional factorial designs is set in a general and unified framework, and a criterion for selecting multistratum fractional factorial designs that takes stratum variances into account is proposed. Application of the general theory is illustrated on designs of experiments with multiple processing stages, including split-lot designs, blocked strip-plot designs, and p...