The first four factors, either individually or in combination with other factors, can contribute to the development of competitive advantage. The likelihood of maintaining sustained competitive advantage is greatly enhanced, however, if resources or capabilities are shrouded in causal ambiguity. The inability to determine how or why a firm is enjoying a competitive advantage will obviously greatly complicate the efforts of competitors attempting to imitate the firm's success. While the resource based view suggests many provocative avenues for research, it also presents researchers with some serious challenges that will require moving beyond current methodologies. First, the study of the resource accumulation process requires longitudinal data if researchers are to appreciate how resource acquisition decisions have contributed over time to the development of competitive advantage.
Longitudinal studies require access to and the collection of data over many years.
While the availability of data is often limited, previous researchers have demonstrated the viability of using longitudinal data collected post hoc. Given the emphasis on asymmetry, researchers pursuing research on competitive advantage must also focus on the unique. Unfortunately, traditional statistical analysis techniques are not well suited for the study of outliers. Regression involves fitting a line that best represents the relationship between the dependent and independent variables, but regression cannot capture information on outliers. In fact, outliers are often discarded from samples because of the undue influence they exert on the regression line.