Six-sigma software using cleanroom software engineering techniques - Motorola's hardware-quality approach applied to software - includes related article on legal primitive evaluation - Technical

Hewlett-Packard Journal, June, 1994 by Grant E. Head

The structured specifications process is used by cleanroom to facilitate control of the process by allowing the development team to focus on small, easily conceptualized pieces. A secondary but very important effect is that productivity is increased. Increased productivity is a natural effect of the team's being focused. Each deliverable is small and the time to produce it is psychologically short. The delivery date is therefore always imminent and always seems to be within reach. Morale is generally high because real progress is visible and is achievable.

Structured specifications also offer a very definite project management advantage. They serve to achieve the frequently quoted maxim that when a project is 50% complete, 50% of its features should be 100% complete instead of 100% of its features being 50% complete. Proper management visibility and the ability to control delivery schedules depend upon this maxim's being true.

Structured specifications are very similar to incremental processes described in other methodologies but often the purposes and benefits sound quite different. For instance, in one case the structured specifications process is called evolutionary delivery.(9) The primary benefit claimed for evolutionary delivery is that it allows "real" customers to examine early releases and provide feedback so that the product will evolve into something that really satisfies customer needs. HP supports this approach and has classes to teach the evolutionary delivery process to software developers.

From the description just given it would appear that each evolutionary release is placed into the hands of real customers. This implies to many people that the entire release process is repeated on a frequent (monthly) basis. Since multiple releases and the support of multiple versions are considered headaches for product support, this scenario is frowned upon. Cleanroom does not make it a priority to place each stage of the product into the hands of real customers.

Looking at the definition of a real customer in the evolutionary delivery process, you realize that a real customer could be the engineer at the next desk. In practice, the product cannot be delivered to more than a handful of alpha or beta testers until the product is released to the full market. This type of release should not occur any more often than normal. In fact, since cleanroom produces high-quality products, the number of releases required for product repair is significantly reduced.

Another type of structured specifications technique, which is applied to information technology development, uses information engineering time boxes.(10) Time boxes are used as a means of preventing endless feature creep while ensuring that the product (in this case an information product) still has flexibility and adaptability to changing business requirements.

HP has adopted a technique called short interval scheduling(11) as a project management approach. Short interval

scheduling breaks the entire project into 4-to-6-week chunks, each with its own set of deliverables. Short interval scheduling can be applied to other projects besides those involved in software development. This is an insight that is not obvious in other techniques.