ODC - Orthogonal Defect Classification

Review and Inspection Triggers

Triggers associated with design review and code inspection activities during development deal primarily with requirements and design. The focus of design review is on ensuring that the functional requirements for the product are complete, understood, and incorporated into the design. Code inspection is undertaken in order to ensure that the design has been interpreted accurately, and coded correctly.

Backward Compatibility

is an area of great concern. As customers migrate to the most recent products, they take with them a body of applications that were used successfully in the previous environment. Customers want these applications to run successfully in the new environment with minimal, if any, required changes.

Lateral Compatability

addresses another critical requirement of customers, that is, that products are able to function with other products of the same generation. Lateral compatibility becomes an increasing challenge throughout later periods of a product's life cycle as more and more products are introduced. Thus, a particular aspect of this area is anticipating accurately the interface requirements of products which do not yet exist.

Design Conformance

related faults are targeted by reviewers or inspectors who attempt to ensure that the interpretation of requirements, structure, or logic matches the corresponding document. These triggers are manifested in the field by customer reported problems which describe situations where the product did not function in a manner that meets the customer's requirements or expectations.

Concurrency

is one of three triggers which are associated with the importance of understanding the details beneath the overall design. This trigger applies to simultaneous use of the same resources, and has implications of security, locking mechanisms, and sometimes performance. For customers, these often appear as long, indefinite waits for a command or function to complete.

Logic Flow

is the second of these triggers, and relates to those occasions when the operational semantics are in question. From a customer viewpoint, the result of a fault in this area is often manifested when a command or program completes, but the returned information is inconsistent or incorrect, but there are many other possibilities as well.

Side Effects

is the third trigger which is best tackled by an experienced developer, well versed in not only the details of the product under development, but also aware of potential impacts on another function or product. When these faults surface in the field, they are characterized by seemingly unrelated symptoms, often difficult to diagnose.

Documentation

is a trigger associated with both the internals information, such as prologues and code comments, and externals such as user guides and installation manuals. Customers rely heavily on accompanying documentation, whether hard copy or on-line, for information about the abilities of the function or product, how to invoke the capabilities, and the results which can be expected. The extent to which the logic flow and interfaces are documented in the code has a significant influence on the prevention of future faults, as well as impacting the degree to which a reported fault can be diagnosed and corrected quickly.

Rare Situation

triggers are also best tackled by experienced developers. They are, by definition, unusual sets of circumstances, for the majority of customers. It is possible, however, that a rare situation for many is a common problem for a particular set of customers. Thus, understanding and interpreting these triggers could become an important element in accommodating particular environments.