COTS v Custom

Before testing and evaluating your design, and ahead of communicating your design back to stakeholders, an important decision needs to be made: can your system be built using existing components, or does it require developing new designs. Using commercial-off-the-shelf (COTS) products can speed up your development, but will likely bring in constraints and trade-offs that weren’t accounted for in your design to date. Alternatively, custom production may remove these constraints, but are generally considered higher-risk, more costly and likely to take longer to produce.

Ultimately, the decision to use COTS, modified COTS or custom development should reflect the importance of your customer requirements.

Example applications

There are three common situations where this decision is key:

Software development: often companies have specific needs for software based on their own internal processes. COTS software often lacks the additional functionality required, and custom development is often too costly if the skills aren’t already in-house. Often plug-ins can be a way to bridge this gap.

Electronics hardware development: the cost of electronics has dropped drastically over recent years with a great increase in function. Devices such as Arduinos and the Raspberry Pi allow for rapid prototyping, but often come with more functionality than required. Using this COTS product to prototype an idea before moving to custom production

Physical prototyping: when designing a physical prototype, using material that you can readily get your hands on is usually a cheaper way to develop your prototype, rather than spending money tooling and configuring machinery. Once you’ve tested the prototype, you’ll have a better idea of how the design might perform and you’ve hopefully figured out some improvements.

Steps

To help you decide whether COTS, modified COTS or custom design is required, you can go back to the concept generation tool: concept combination table (see Ulrich & Eppinger 1995, p96).

• Create columns for the subsystems described in subsystems
• List all the COTS, modified COTS or custom options to achieve the functions required of that subsystem
• Choose an assembly that best helps you to meet your customer requirements

Note: it may be worthwhile taking these ideas to an evaluation matrix.

Hints

• Comparing COTS, modified COTS and custom design becomes a good comparison for the evaluation of designs if your group has narrowed to a single design.
• Consider the topic in relation to different phases of production: the needs of proof-of-concept and development stages are very different

Core resources

• McKinney, D., Impact of COTS Software and Technology on Systems Engineering, presentation to INCOSE Chapters [PDF]
• Ulrich, K.T., and S.D. Eppinger, 1995. Product Design and Development. McGraw-Hill. Chapter 5 - Concept Generation [PDF, 25 pages] (from concept generation topic){: .link-ext target=”_blank” }