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[Methodology]
A compendium of models and methods:
Maturity Model
Key KPA's are assessed to determine an approximate equivalence to a SEI SW-CMM level.
Risk Model
Linear model that determines the software life-cycle development capability and operational readiness by assessing the best practices that are implemented and how well the organization performs against it.
Cost and Quality models
Product development effort and schedule models for system design, programming, test, service/support and project management.
Quality models provide product defect rate projections and permit reconciliation of defect data from early discovery through system test, if available.
Enterprise model
Linear model that determines the robustness and long-term viability of the Enterprise. Support Model provides support requirements (L3-L1) based on product and customer data.
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[The Quality Equation]
Product Defects = Total Inserted Defects - (Early Discovery Defects + Integration and System Test Defects)
The Total Inserted Defects can be determined from past history of a given project team in terms of its proficiency in engineering a product through its entire life cycle. In other words, it can be related to the level of maturity of a project team having a well defined and well managed organization in terms of being able to track projects and apply prior experience effectively towards repeatable success and continuous improvement.
Early Discovery Defects are the defects that are found through design inspections, code reviews and unit testing. Therefore, this can be related to the capability of a development team in terms of being able to adequately review and verify requirements, design and code for correctness/conformance to specs.
Finally, Integration and System Test Defects are the defects that are exposed during the formal test phase (also referred to as the Independent Test phase) of the project. The target or acceptable defect rate and complexity for a given product determines the effort needed in this phase.
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[Early Defect Removal and Development Proficiency]
The removal of defects in the earlier stages of development (prior to formal test) depends directly on the software engineering capabilities of the development team in terms of experience level to conduct effective design/code reviews, use of standard practices, configuration management, etc. This can be determined directly by tracking such defects from the start of development and matching against the Rayleigh curve.
Table 2: Early discovery defects found as a percent of total inserted defects for 5 levels of development proficiency. These are the defects that are found during design reviews, code inspections, unit test,etc.,before the code is committed to formal test. Multiple values delimited by commas are for first, second and n+2 release, respectively. The COCOMO numbers are based on a Delphi process.
The Rayleigh Defect curve predicts that Early Defect removal rate should be 1-(0.17+(1-0.95)) = 78%, but it implies a certain capability. Based on Table 2, the Rayleigh curve appears to model High to V. High capability.
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