The processes of V&V are key activities for accrediting all types of models and simulations. With the goal of providing a basis to determine if the models, simulations, and analysis tools are acceptable for use for a specific purpose, there are three pieces of information to capture and address from the modeling and simulation (M&S) characterizations as part of this process:
- The question(s) to be answered and the particular aspects of the problem that the M&S will be used to help address.
- The decisions that will be made based on the M&S results.
- The consequences resulting from erroneous M&S outputs.
Information for the V&V of models, simulations and tools used to develop software code can be found in NASA-STD-7009, Standard for Models and Simulations, and in NPR 7150.2. Center requirements and associated processes flowed down from these two documents address numerical accuracy, uncertainty analysis, sensitivity analysis and V&V of models and simulations.
The use of NASA-STD-7009 in fulfilling the requirements of NPR 7150.2 is described in Topic 7.15 - Relationship Between NPR 7150.2 and NASA-STD-7009. The Topic also provides a list of additional resources for V&V of models and simulations used in the software development life cycle.
Per section 4.4 of NASA-STD-7009, the following basic activities are to be performed for verification of models and simulations:
- Document verification techniques and the conditions under which the verification was conducted.
- Document any numerical error estimates for the results of the computational model.
- Document the verification status.
Per section 4.4 of NASA-STD-7009, the following basic activities are to be performed for validation of models and simulations:
- Document techniques used to validate the models and simulations for their intended use.
- Document the conditions under which the validation was conducted.
- Document any validation metrics and any validation data sets used.
- Document any studies conducted.
- Document validation results.
To better understand the uncertainties affecting the results of the models and simulations, follow the required steps in section 4.4 of NASA-STD-7009 and the steps for assessing and reporting the credibility of model and simulation results found in sections 4.7 and 4.8 of NASA-STD-7009.