Once we have gathered the raw data that we want to include in our statistical analyses we generally need to clean it up so that it can be merged it into a single data file. In this chapter we will learn how to create the data gather and merging files we saw in the last chapter. The chapter also includes information on recoding and transforming variables. This is important for merging data, but will be very useful information in later chapters as well. If you are very familiar with data transformations in R you may want to skip onto the next chapter.