In spite of recent methodological developments related to quality assurance in mixed methods research, practical examples of how to implement quality criteria in designing and conducting sequential QUAN -> QUAL mixed methods studies to ensure the process is systematic and rigorous remain scarce. This article discusses a three-step procedure for securing the quality of the meta-inferences generated from sequential employment of quantitative and qualitative methods and offers several validation strategies specific to a sequential QUAN -> QUAL mixed methods design: applying a systematic process for selecting participants for qualitative follow-up, elaborating on unexpected quantitative results, and observing interaction between qualitative and quantitative study strands. The discussed procedures are illustrated using a mixed methods study of graduate student engagement in learning applied research methods online.