 In this context, methodological unity often takes the form of borrowing standards and techniques for the application of formal and empirical methods. They range from calculational techniques and tools for theoretical modeling and simulation of phenomena to techniques for modeling of data, use of instruments and conducting experiments (e.g., the culture of field experiments and, more recently, randomized control trials across natural and social sciences). A key element of scientific practice often ignored by philosophical analysis is expertise. As part of different forms of methodological unity, it is key to the acceptance and successful appropriation of techniques. Recent accounts of multidisciplinary collaboration as a human activity have focused on the dynamics of integrating different kinds of expertise around common systems or goals of research (Collins and Evans 2007, Gorman 2002). The same perspective can accommodate the recent interest in so-called mixed methods, e.g., different forms of integration of quantitative and qualitative methods and approaches in the social sciences. 