12  Combining data

Learning objectives

12.1 Context

Data is often split over multiple tables. We saw this in the previous section. Sometimes we need to combine information from multiple sources.

12.2 Joining tables

12.2.1 The importance of an indentifier

LO: a common identifier (more generally, unique identifiers are really important - e.g. mention LMM)

12.2.2 Joining tables

LO: joining tables

12.3 Cleaning data

12.3.1 Variable naming

LO: variable naming (janitor package)

12.3.2 Encoding issues

LO: encoding issues

12.3.3 Missing data

LO: dealing with missing data

12.4 Summary

Key points