This chapter presents an overview of different methods of data collection (intra-textual, inter-textual and cross-textual variable analyses) and explains and discusses in detail their advantages and disadvantages. The chapter approaches the methods in question in two ways: firstly, some fundamental problems for each method are addressed on an abstract level, then these problems are illustrated using examples from the German-speaking territories of the fifteenth and sixteenth centuries, a period of significant spelling variation. The chapter concludes that each method of description of itself favours certain types of explanatory hypotheses, and makes readers more aware of the presuppositions that may affect the outcome of an investigation, even before data analysis.