Publisher Summary This chapter focuses on important guidelines that a modeler should follow to identify problems for which the model has been designed. There are only three sources of data including data obtained from outside the organization, data on hand, and data developed specifically for the project. These types of data are different from each other in numerous ways; however, they have some common characteristics too. This chapter discusses how data can be utilized in data mining to support a business model, irrespective of the data source. Business models can be created from the opinions of various stakeholders (indirect data). Such models may be invaluable as expressions of opinion, but without empirical data to support them, they remain exactly that, opinion. The ancient Greeks had many opinions about the nature of the world, but they much preferred logical thinking as opposed to evaluating what actually happened around them. And getting the model right requires an aptly constructed model with accurate data.