We sought formal consensus on the appropriateness of Video-assisted Thoracoscopic Surgery (VATS) talc pleurodesis and bedside thoracostomy talc slurry by use of a well established method - the RAND/UCLA appropriateness method (RAM). We recruited an expert panel of respiratory physicians, oncologists, and surgeons under the leadership of experts in health services research. The panellists were provided with evidence from a systematic review and then were taken through two rounds of opinion gathering, the first individually, the second as a group. The purpose is not to force consensus, but to find scenarios where there is agreement on the appropriateness or inappropriateness of a treatment and scenarios where there is disagreement. In scenarios where the diagnosis was proven and expectation of life beyond six months, pleurodesis was deemed appropriate. If there was no tissue diagnosis surgical VATS was preferred. The response to a trial aspiration played a major part in the recommendation for or against pleurodesis. The attitude to breathlessness was incongruous; it is the target of palliation yet some interpreted it as performance status and thus a contraindication. Although the RAM is well developed and in widespread use, we found it worryingly unreliable and to be used with caution.