Making inferences about elections and Public oPinion using incidentally collected data

This chapter discusses the use of large quantities of incidentally collected data (ICD) to make inferences about elections and public opinion. ICD is data that was created or collected primarily for a purpose other than analysis (Sjoberg, Mellon, and Peixoto 2017). The internet has expanded the availability and reduced the cost of ICD with data sources including internet searches, social media data, and civic platforms. This chapter focuses on the uses of ICD in elections and public opinion (EPOP) research and the challenges that researchers face in using it effectively.