Systems and methods for measurement and management are disclosed that provide complex measurements cost-effectively at very high accuracy. These methods and systems in some cases achieve measurement accuracy exceeding the accuracy of the reference standards they rely on, and eliminate expensive and disadvantageous recalibration procedures. The accurate measurements are integrated with management functions, applying the measurement data to meet objectives of the integrated system and workflow goals of its user. The disclosed systems and methods comprise an explicit or expressly represented model both of themselves and of candidate external systems to be measured and managed. The models may be configured and reconfigured by the owner-user through either local or remote means. The system intelligently reconfigures itself to adapt dynamically to the conditions of measurement and the user's and system's goals at each moment. In an embodiment, the system includes high-accuracy and reconfigurable components including a meter or control head adapted for user precision assembly and maintenance that computes and displays or communicates the measurements, displaying measurements in desired units, grouping functions according to ergonomic and cognitive principles based on the activity and workflow of a user in relation to the internal model. The use of models permits the system to compute and provide complex and inferred measurements of ultimate interest to the user, including quantities that cannot be directed measured and only can be determined through reasoning or computation by applying models to raw measurement data. The precision-assembly modular electromechanical design further permits an owner-user to precisely assemble, maintain, modify the apparatus and calibrate the equipment for accuracy.