Modern structures require more complex and accurate designs than ever before. In order to achieve an economic and safe design it is necessary to account for the uncertainties in design variables. This paper presents a technique in which the science of design of experiments (DOE) is employed to assess in modern structure design. A case study of a simple structure that is idealized as a simply supported beam is investigated. The design variables are categorized according to their sources as: load, geometry and material types. Each variable value is assumed to vary within a given numerical distribution. The deflection at the mid span of the structure is considered as the performance response of interest. DOE is applied to evaluate the effect of uncertainty within the design variables on the performance response. It is also used to calculate the interaction effect between design variables. This technique yields a better understanding of how the design variables are interacting and how this will affect the overall performance of the structure. It is believed that the intelligent use of DOE techniques will help in the design of safer and more economic structures.