Since the last international guidelines were published in 2014 on the evaluation and management of primary hyperparathyroidism (PHPT), new information has become available with regard to evaluation, diagnosis, epidemiology, genetics, classical and nonclassical manifestations, surgical and nonsurgical approaches, and natural history. To provide the most current summary of these developments, an international group, consisting of over 50 experts in these various aspects of PHPT, was convened. This paper provides the results of the task force that was assigned to review the information on the management of PHPT. For this task force on the management of PHPT, two questions were the subject of systematic reviews using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) methodology. The full report addressing surgical and nonsurgical management of PHPT, utilizing the GRADE methodology, is published separately in this series. In this report, we summarize the results of that methodological review and expand them to encompass a much larger body of new knowledge that did not specifically fit the criteria of the GRADE methodology. Together, both the systematic and narrative reviews of the literature, summarized in this paper, give the most complete information available to date. A panel of experts then considered the last set of international guidelines in light of the newer data and assessed the need for their revision. This report provides the evidentiary background to the guidelines report. In that report, evidence from all task forces is synthesized into a summary statement and revised guidelines for the evaluation and management of PHPT.