Generically speaking, COTS selection should occur through trade analysis resulting in the item that meets the 80/20 rule at the least cost and within schedule constraints. More specifically, a standardized approach, as defined by the NASA Jet Propulsion Lab (JPL) consists of the following steps:
Certain exceptions may occur for items of high criticality or items that have specific maintainability, supportability, constraints, etc. Exceptions may also occur for items that are difficult to test and integrate and are therefore cost and schedule prohibitive.
There are many decision analysis tools (Decision Tree) and methods (analytical hierarchy process (AHP)) that can be used to draw some sound statistical solutions when evaluating COTS alternatives and to assist with completing the first 5 out of 7 steps of the standardized JPL COTS procedure.
There are also a number of COTS product selection methodologies for use in addition or substitute to the JPL COTS procedure:
- Off-The-Shelf Option (OTSO)
- Social-Technical Approach to COTS Evaluation (STACE)
- Procurement-Oriented Requirements Engineering (PORE)
- COTS Acquisition Process (CAP)
- The contract based COTS performance selection (CBCPS)
Figure 1: Overview of the CBCPS method process.
The CBCPS method lends itself more for safety critical systems. See COTS Product Selection for Safety-Critical Systems in the References section for more information.