Rocha et al. developed a discriminatory score in a cohort of 30 patients with reversible cerebral vasoconstriction syndrome (RCVS) and 80 patients with non-RCVS arteriopathy, and they validated it in a separate cohort of RCVS and its mimic, primary angiitis of the CNS (PACNS). They found that a score that evaluated for recurrent/single thunderclap headache, carotid artery involvement (less likely with RCVS), vasoconstrictive trigger, female sex, and subarachnoid hemorrhage could accurately distinguish RCVS from other intracranial arteriopathies. In response, Drs. Yuan and Hu highlight some limitations of the study, including the use of retrospective study data, limited sample size, inclusion of 2 variables relying on the patient’s subjective recall (vasoconstrictive trigger and thunderclap headache), lack of a gold standard, and the need to validate the score’s ability to distinguish RCVS from arteriopathies other than PACNS. They propose using additional readily available clinical variables and imaging markers such as vessel wall imaging and transcranial color-coded sonography to further refine and validate the score. Responding to these comments, Drs. Singhal and Rocha note that several of these limitations were acknowledged in the article. They counter that advanced vessel wall imaging or biomarker studies are unlikely to improve the near-perfect performance of RCVS2 scores >5 or <2 in their study but may have some utility in patients with intermediate scores. They argue that patients’ recall of thunderclap headache is likely to be reliable, given the uniqueness of the experience, whereas patients may underreport vasoconstrictive triggers such as illicit drugs and over-the-counter medications. This exchange underscores the challenges and disagreements that may be encountered when developing and refining clinical scores for neurologic conditions.