Requirements quality theoretical introduction

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How to assess the quality of a requirements specification.

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Requirements quality theoretical introduction

  1. 1. Requirementsquality<br />A theoreticalintroduction<br />
  2. 2. Contents<br />2<br />Currentsituation in swdevelopment<br />Whyrequirements are so important<br />Whatisthequality target<br />ARM project<br />RequirementsQualityAnalyzer: RQA<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />
  3. 3. Currentsituation in sw. development<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />3<br />
  4. 4. Whyrequirements are so important<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />4<br />Based on requirements<br />15.9%<br />13.0%<br />8.2 %<br />2.9 %<br />+40% directly related to requirements<br />
  5. 5. Whyrequirements are so important<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />5<br />Requirements:<br />Should be signed as a contractbetweendeveloper and customer<br />Are thebasisfor software design<br />Man role alsoduringthetestingphase<br />
  6. 6. Whyrequirements are so important<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />6<br />Software projects are more and more complexoverthe time<br />The sooner a problemistackledthelessthesolutioncosts<br />
  7. 7. Whatisthequality target<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />7<br />Accordingto IEEE Std. 830 – 1998:<br />Correct<br />Unambiguos<br />Complete<br />Consistent<br />Ranked (importance and stability)<br />Verifiable<br />Modifiable<br />Traceable<br />
  8. 8. Whatisthequality target<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />8<br />According to ESA PSS-05-03:<br />SR04 Each software requirement shall include an identifier.<br />SR05 Essential software requirements shall be marked as such.<br />SR06 For incremental delivery, each software requirement shall include a measure of priority so that the developer can decide the production schedule.<br />SR07 References that trace software requirements back to the URD shall accompany each software requirement.<br />SR08 Each software requirement shall be verifiable.<br />SR11 The SRD shall be complete.<br />SR12 The SRD shall cover all the requirements stated in the URD.<br />SR13 A table showing how user requirements correspond to software requirements shall be placed in the SRD.<br />SR14 The SRD shall be consistent.<br />SR15 The SRD shall not include implementation details or terminology, unless it has to be present as a constraint.<br />SR16 Descriptions of functions ... shall say what the software is to do, and must avoid saying how it is to be done.<br />SR17 The SRD shall avoid specifying the hardware or equipment, unless it is a constraint placed by the user.<br />
  9. 9. Whatisthequality target<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />9<br />"I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to Earth"<br />
  10. 10. Whatisthequality target<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />10<br />Allthese targets seemto be clear<br />RM tools (e.g. DOORS or IRQA) helpus in some cases:<br />Modifiable, traceable…<br />But, letusdoublecheckthese targets<br />Are allthesequalitygoalsreallyunambiguous<br />Spanishproverb: «In theblacksmith’s home woodenknife»<br />
  11. 11. ARM project<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />11<br />ARM: <br />AutomatedRequirementMeasurementby NASA<br />«The objective of the ARM toolistoprovidemeasuresthat can be usedbyproject managers toassessthequality of a requirementsspecificationdocument»<br />The ARM tool scans a requirements specification document for key words and phrases and generates a report file summarizing the specific quality indicators<br />The tool is not intended to evaluate the correctness of the specified requirements; it’s an aid to “writing the requirements right”, not “writing the right requirements”<br />ARM analyzes a whole specification, req by req, and is able to show which aspects of a requirement should be avoided<br />
  12. 12. ARM project<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />12<br />Objectivelymeasuredindicators vs. qualityattributes<br />
  13. 13. Requirements Quality Analyzer<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />13<br />RQA (Requirements Quality Analyzer) is a toolby The REUSE Company<br />In thesameway as ARM, RQA try toobtainobjectivequalitymeasurements<br />RQA works, nowadays, in English and Spanish<br />The maindifferencesbetween RQA and ARM:<br />RQA includesmuch more metricsthat ARM<br />RQA isfullyconnectedtoDOORS and IRQA<br />RQA isfullycustomizable<br />RQA uses linguisticcapabilities and notkeywordspotting<br />RQA uses semanticcapabilitiestoprovide global metrics<br />RQA allowsyou cicles of changetext and assessquality as many<br />times as needed<br />
  14. 14. Requirements Quality Analyzer<br />Requirements quality (A theoretical introduction) - (C) The REUSE Company<br />14<br />More informationaboutRequirements Quality Analyzer:<br />http://www.reusecompany.com<br />

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