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The ontology you choose to use depends on your local goals and local data. As long as your primary purpose is to understand and show how the i2b2 webclient works, the i2b2 demo ontology is sufficient. If your goal is to set up i2b2 for research use, one of the ACT ontologies will be more useful. In general, to set up an i2b2 instance to support research, start with the ACT Ontology. This Ontology includes a wide range of terminologies that should cover most code-sets you'll find in your EMR data. OMOP refers to a data architectureCommon Data Model, so if you are using this format model locally, then ACT on OMOP will be the most relevant.

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