Use a Maximum Spread Design

Selection of test items so that they are as dissimilar a possible to each other is accomplished by choosing items which are projected far from each other and on the periphery of the plot. Such designs are useful for answering the question of whether or not the properties have an influence. A maximum spread design wa used to determine whether modification of the solvent would increase the endo/exo stereoselectivity in the reduction of an enamine from camphor. The answer was negative [17 a], 

Selections which afford a maximum spread also provide a good initial screening design for totally new reactions. Poor candidates can be eliminated early and the study can be continued with more promising candidates, see Sect. 4.6.2. 

---