Experimental Design and Analysis

This chapter provides the ergonomics/human factors (E/HF) practitioner and researcher with practical advice on how to design studies and analyse the resulting data to achieve effectiveness and efciency. In the 1930s, there was a major revolution in how experiments are designed. We moved from the traditional physical sciences model of ‘vary one factor at a time; keep all other factors xed’ to a philosophy that emphasises varying multiple factors in the same experiment. What made this revolution possible was the development of sophisticated statistical techniques (e.g. analysis of variance [ANOVA]) that allowed for the parsing of the effects of each factor, and their combinations, and the testing of each effect against the normal variation experienced in any experiment. This is the model for experimental design and analysis we still use in E/HF.