The PICO model is a general model in building problems of evidence-based medicine (EBM). However, with the deepening and refinement of the medical research and the rising of qualitative research, the PICO model could not satisfy all problems. This article introduces the expansions of the PICO model and puts forward the SPIDER model according to the qualitative problem and its relationship with the PICO model, which can build the best search strategy of clinical problems in a short time.
