V & V Lifecycle Methodologies


Therefore, Inspections are the foundational process for lifecycle methodologies, especially those exploiting the predictive and management enabling capabilities of Rayleigh models. Ironically, Inspections are but one of hundreds of techniques recommended by lifecycle frameworks, and are more effective and efficient than many, if not most lifecycle framework V&V techniques. And, Inspections are an order of magnitude more effective and efficient than testing, minimizing the need for testing-intensive V&V.

Inspection Process Measurability
Inspections are a highly structured, well defined, step-by-step process for identifying defects for elimination. Because Inspections can be so concisely characterized and described, all aspects of Inspections can be measured, including total effort required, as well as the efficiencies of every aspect of Inspections. On average, a single Inspection may take 15 hours and uncover as many as 15 to 45 defects in sof defects in hard-coded software alone. Edward Weller [12], Glenn Russell [13], and Robert Grady [16] have given the earliest expositions of Inspection econometrics and models, but other research available on the World-Wide-Web has offered explicit econometric Inspection models [17].

Lifecycle Methodology Accuracy
As previously mentioned, lifecycle methodologies are based on the use of Rayleigh models. Rayleigh models are quantitative techniques for accurately predicting final software product quality within a tenth of a defect, expressed in defect density metrics and measures, once they have been calibrated to empirical data [9, 11].

Rayleigh model-based lifecycle methodologies have been successfully applied on large-scale monolithic software lifecycles, most notably between 1986 and 1996 [8, 9, 10, 11]. Rayleigh model-based lifecycle methodologies resulted in the development, conversion, and maintenance of [8, 9, 10, 11]:

  • Eight system-level software products.
  • Five compilers.
  • Five major system utilities.
  • Eleven million lines of online help information.
  • Thirty-two thousand pages of manuals.
  • A five hundred thousand line automated help utility.
  • Eleven hundred lines of questions and answers.
  • Native support for twenty-five international languages.
  • Five and a half million new sources lines of code.
  • Thirty billion converted source lines of code.

But this wasn't the only program, as Rayleigh model-based V&V lifecycle methodologies have been applied on many different software lifecycles. These software lifecycles ranged from seventy to seventeen hundred new source line of code systems, all managed to within a tenth of a defect of accuracy by the time software was delivered, extending into field use and measurement [11]. To deny the existence, applicability, usefulness, and utility of Rayleighbased lifecycle methodologies would be a matter of personal choice, but certainly not invalidity.

What do Lifecycle Methodologies Do?
Lifecycle methodologies are compliant with the generic definition of V&V by the IEEE Standard of Glossary of Software Engineering Terminology, which states that V&V is the process of determining whether:

  • Requirements for a system or component are complete and correct.
  • Products of each development phase fulfill the requirements or conditions imposed by the previous phase.
  • Final systems or components comply with specified requirements.

However, lifecycle methodologies are both more and less than lifecycle frameworks, especially those recommended by IEEE standards [6, 7]. Lifecycle methodologies are more, in the sense that they are predictive, measurable, and highly effective. Lifecycles are less, in the sense that they are lean, streamlined, and reduced to only the most essential, but highly–effective V&V techniques. Popular literature fails to even begin to recognize the existence and applicability of lifecycle methodologies [2, 3]. However, there is a new wave of literature expounding the benefits of even more streamlined and efficient forms of lifecycle methodologies emerging [18, 19, 20, 21, 22, 23].

Costs & Benefits
The most thorough examinations of the costs and benefits of lifecycle methodologies were done by Stephen H. Kan [11], Robert

About the author

David Rico's picture David Rico

David F. Rico is an ROI consultant. He’s worked for NASA, DARPA, DISA, Air Force, Navy, and participated in over 15 SW-CMM® initiatives. He’s been an international keynote speaker, published numerous articles, holds a BS in Computer Science, MSA in Software Engineering, and is pursuing a doctorate in IT. You can reach David at davidfrico.com.

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