Stress testing (micro-hydraulic fracturing) is recognized by petroleum industry as the most direct method of determining the minimum in situ (closure) stress for a given reservoir rock and the surrounding formations. In general, it is variations of in situ stress between formations that dominates hydraulic fracture height growth and overall fracture geometry. Misleading interpretations of stress test data (cased or open hole) can lead to significant errors in the prediction of stress contrast between the producing and bounding rock layers as well as an erroneous estimation of closure stress in the productive interval. In either case, hydraulic fracture treatment designs based on this information may not be designed optimally and the subsequent interpretation of the fracturing treatment pressure response may not be correct. This paper presents an evolutionary approach in the analysis of stress test data which leads to more consistent results that relate directly to actual fracture treatment pressure responses. Although the emphasis in this paper is on cased hole stress test data interpretation, the methodology presented is also applicable to open hole stress testing and larger scale pump-in/shut-in (i.e. calibration or minifrac) pressure falloff responses.