Sophie is preparing her data for quantitative analysis. She is in the process of randomly calling back 20% of the study's participants to confirm that they were treated respectfully and professionally, that the study was conducted correctly, that they met the appropriate screening criteria, and that the research assistants did not engage in curbstoning. Sophie is engaging in which of the following data preparation steps?

Sophie is preparing her data for quantitative analysis. She is in the process of randomly calling back 20% of the study's participants to confirm that they were treated respectfully and professionally, that the study was conducted correctly, that they met the appropriate screening criteria, and that the research assistants did not engage in curbstoning. Sophie is engaging in which of the following data preparation steps