RESULTS: Five guidelines matched the inclusion criteria and were assessed. A multinational collaboration produced 2 of 5 guidelines. The observers recommended (with modifications) only 2 guidelines. Clarity of presentation, scope and purpose (objectives and health questions target the population) received the best score, whereas the applicability of the guideline received the lowest score. International development positively influenced the scope and purpose of the guidelines. Moreover, improved scores were achieved when the stakeholders were fully involved and had editorial independence.CONCLUSIONS: As assessed by the AGREE II criteria, the quality of the various guidelines was extremely inconsistent. Guidelines with higher AGREE II scores were those developed with the participation of European scientific societies.OBJECTIVES: A project to assess the existing literature and the quality of past guidelines on the management of primary spontaneous pneumothorax was developed by the Italian Society of Thoracic Surgeons, with particular focus on the assessment of the methods used to produce such recommendations.METHODS: The different items and domains within each guideline were assessed using the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument and scored on a 7-point scale.