PURPOSE OF REVIEW: To evaluate design considerations for an osteoporosis large simple trial (LST). RECENT FINDINGS: There is a growing need for more comparative effectiveness studies in osteoporosis. However, the design of such studies is challenged by issues surrounding study design, choosing comparator therapies, participant and outcome selection, data acquisition and data analysis. SUMMARY: LSTs are real-world studies that can have high levels of generalizability, if designed properly. We propose novel approaches to LSTs focusing on some of the challenges associated with comparative effectiveness research in osteoporosis. In this review, we discuss these considerations in the context of bisphosphonate active comparator initiation and discontinuation trials, while presenting advantages and disadvantages of the various design aspects for such studies. © 2013 Wolters Kluwer Health / Lippincott Williams & Wilkins.