An experimental space comprising levels of factors is designed according to an incomplete block design and an experimental space comprising levels of factors is designed by random selection. Separate combinatorial high throughput screening experiments are effected on each experimental space to produce sets of results and best results are selected from the sets. A system for conducting an experiment includes a reactor for effecting a combinatorial high throughput screening method on an experimental space to produce results and a programmed controller that defines an experimental space comprising levels of factors according to an incomplete block design and defines an experimental space comprising levels of factors by random selection.