This article provides clear and practical guidelines for researchers seeking to use national secondary datasets to conduct evidence-based research. Drawing from our own experiences, we discuss a six-step research process model (Bryan et al., 2010, 2017) to help researchers navigate the use of these datasets. We present examples from the school counseling literature using these datasets and discuss the implications for evidence-based practice. Recognizing that quantitative research with secondary datasets has the potential to produce unintended harm to children with marginalized identities, we discuss the value of a QuantCrit lens in the research process. This article will increase researchers' understanding of these datasets, demystifying the process so that they may use them more effectively to inform practice and policy.