LAUSR

The most common approach to experimental design employed by many scientists today is OneVariable-At-a-Time (OVAT), in which one variable at a time is changed, keeping all other variables in the experiment fixed (or constant); then, the change in the resulting outcome is observed. Quantifiable outcomes of the experiments are often measured using scientific instruments or equipment, e.g., in spectroscopic and microscopic techniques. The variations observed in the outcome of an experiment may stem from two sources: a) it may be a direct consequence of the intentional change in the input variable, usually the case if the outcome variable is correlated with the changing input variable; or b) it may be an error or variation in the measurement system (Fig. 1). Drawing correct logical conclusions when simultaneously working with nanoscale materials and devices and operating the measurement equipment near or at its performance limit, requires appropriate quantification of all sources of variability.