Transient ischemic attack (TIA) is a harbinger of recurrent stroke and poor cardiovascular outcomes.Early evaluation and targeted management substantially reduce the risk of subsequent adverse events. 1,2 Furthermore, specialized clinic-based care is associated with higher adherence to evidence-based secondary stroke prevention strategies and improved outcomes. 3 Bravata et al 4 provide the findings from the Protocol-Guided Rapid Evaluation of Veterans Experiencing New Transient Neurological Symptoms (PREVENT) quality improvement (QI) program.They highlight that the PREVENT program was conceived on the principles of a learning health care system (LHS). The multicomponent PREVENT intervention comprised the following 5 domains: development and sharing of clinical protocols across participating sites, provision of a data-driven web-based interactive and customizable dashboard (the PREVENT hub), professional education for health care providers, electronic health record (EHR) tools, and ongoing QI support, including a virtual collaborative platform. 5 The results of the intervention were primarily measured by monitoring adherence to the following 7 guideline-recommended processes of care for patients with TIA: anticoagulation for atrial fibrillation, antithrombotic use, brain imaging, carotid artery imaging, high-or moderate-potency statin therapy, hypertension control, and neurological consultation. The prespecified primary outcome was a without-fail rate, defined as the proportion of participants with TIA who received all of the individually indicated processes of care. Of note, this outcome measure does not provide partial credit toward achieving some of the applicable processes of care. Therefore, a secondary consolidated measure of care was also included that described the proportion of care that patients received for which they are eligible. The program was implemented across 6 Veterans Affairs (VA) hospitals as a cluster design, and the investigators compared outcomes between the 6 participating sites and 36 matched nonparticipating VA hospitals.The PREVENT intervention was conducted in 3 phases; however, the sites were not randomly assigned to the intervention, which would have been the case in a classic step-wedge trial (SWT) design. 6 The SWT is a design that is gaining traction in health services research in which the intent is to establish the effectiveness of implementation strategies for evidence-based interventions at a cluster or group level. Although the design provides logistical advantages (eg, a phased rollout across sites or clusters), it does not compromise scientific rigor and, if correctly implemented, provides causal estimates. Evaluation of QI interventions warrants a rigor similar to that of randomized clinical trials (RCTs), and PREVENT's rationale and setting were suitable for an SWT design. The design limitations are further compounded by a selective nature of the 6 VA hospitals where the program was implemented. Although the logistical, behavioral, political, and administrative challenge...