Multi-user system for creating and maintaining a medical-decision-making knowledge base

A multi-user system for creating and maintaining a knowledge base is implemented on a variety of computer systems, including single-user personal computers, networked personal computers, and data communications networks, including the Internet. The system has a graphic user interface which can be easily learned by non-programmers. The knowledge base is displayed as a hierarchical multiplicity of nodes, in which each node is related to one or more superior nodes. Title of text, rules, references, and attributes associated with each node are displayed, and may be modified. Simulation is used to verify the knowledge base once generated. Data may be extracted from the bases in the form of hard-copy books, databases for downloading into Web browsers, and databases for downloading into hand-held computers including a multiplicity of grids, and a multiplicity of branches in the form of a logic tree. The user may choose one of the alternative display formats, and the hierarchy can be displayed in either collapsed view or expanded view. Interference between two or more users accessing the system concurrently is prevented by a locking and authorization subsystem, which also prevents unauthorized access to the environment. The system provides an organization of workflow into a multiplicity of development stages. Each such stage has associated with it an authorization level, developers working on the system concurrently are limited by these levels to access only particular stages and levels of development.