A review of: Postell, William Dosité. “Further Comments on the Mathematical Analysis of Evaluating Scientific Journals.” Bulletin of the Medical Library Association 34.2 (1946): 107-9. Objective – To predict future use of journal titles for making subscription decisions. Design – Retrospective cohort study. Setting – Louisiana State University School of Medicine Library in New Orleans. Subjects – All library users, estimated to consist of primarily faculty members or their designees such as research assistants. Methods – Estelle Brodman’s previous citation analysis and reputational analysis (1944) that produced a list of eleven top-ranked physiology journal titles served as the catalyst for Postell’s retrospective cohort study. Postell compiled data on all checkouts for these specific eleven journal titles in his library for the years 1939 through approximately 1945. Main Results – Postell performed a Spearman rank-difference test on the rankings produced from his own circulation use data in order to compare it against journal title rankings produced from three other sources: (1) citation analysis from the references found in the Annual Review of Physiology based upon a system pioneered in 1927 by Gross and Gross; (2) three leading national physiology journals; and, (3) a reputational analysis list of top-ranked journals provided by the faculty members at the Columbia University College of Physicians and Surgeons Department of Physiology. Postell found a relatively high correlation (.755, with 1.000 equaling a perfect correlation) between his retrospective cohort usage data and the reputational analysis list of top-ranked journals generated by the Columbia faculty members. The two citation analyses performed by Brodman did not correlate as highly with Postell’s results. Conclusion – Brodman previously had questioned the use of citation analysis for journal subscription purchase decisions. Postell’s retrospective cohort study produced further evidence against basing subscription purchases on citation analysis. Postell noted that the citation analysis method “cannot always be relied upon as a valid criterion” for selecting journals in a discipline.