In the first part of the book, we presented a precision checking technique based on escaping arcs. However, it is not uncommon to have a certain degree of unfitness when we measure precision, e.g., invisible or duplicate activities, or simply produced by small known mismatches between model and process. This chapter provides an overview on the use of alignment techniques as a pre-processing step to provide meaningful precision results in unfitting scenarios. In the next chapter, we will present some variants of this technique more suitable for some cases.