Data analysis is the process of evaluating, transforming, classifying, and modeling data. This chapter deals with the evaluation to classification process. The market research process can be iterative. It is possible to "jump" back and forth between the collection and analysis of data. Once the data collection is completed, it is quite tempting to immediately start data analysis. There are two main steps to initial data analysis: cleaning up the data (which itself is split into a screening phase and a diagnosis/editing phase) followed by the preparation and formatting of data for analysis. Cleaning up data consists of assessing the data to check for errors and inconsistencies, and then developing solutions to address the errors as well as documenting how you will be handling them. The final step of cleaning data is the preparation of the data for more advanced analysis. While producing summary tables can be useful, the researcher might decide to adjust the variables for advanced analysis.