ABSTRACT

Data verifi cation and data validation are typically sequential steps. For example, data verifi cation is performed during or at the end of data collection activities, whereas data validation is conducted after this, most often by an individual who is independent of both the data collector and the data user. Data validation begins with the outputs from data verifi cation (EPA 2002). Data verifi cation and data validation occur prior to the formal Data Quality Assessment (DQA) process that is discussed in Chapter 8.