ISMA 15 conference: Better Estimates by Measuring Requirement Quality
Simon Wright (Symtech Ltd UK)
- Factors affecting quality of a functional size estimate
- The Correctness, Completeness and Consistency of user requirements
- Natural Language Processing techniques to quantify quality
- Requirement Patterns for measurable requirements
- Writing requirements that are measurable
Benefits for Participants:
- How to measure the quality of input User Requirements
- How to improve the quality of input User Requirement
- Guidelines for writing requirements that are measurable.
The quality of a functional size estimate is a function of several factors including: precision, accuracy and repeatability. The main factor affecting the precision of an estimate is the completeness of the user requirements. If a requirement or user story has been missed, then the estimate is imprecise. The main factor affecting the accuracy of an estimate is the correctness of the user requirements. If a requirement is incorrectly phrased, then the estimate is inaccurate. The main factor affecting the repeatability of an estimate is the consistency of the user requirements. If requirements use terms inconsistently then they need to be interpreted; different estimators are likely to use different interpretations and thereby produce different estimates.
Assuming that the process of transforming requirements into an estimate is carried out using a standardised method then the quality of the estimate is directly proportional to the quality of the input requirements.
Modern Natural Language Processing techniques can be used to quantify the quality of the user requirements in terms of the Correctness, Completeness and Consistency, (CCC), of individual as well as sets of requirements. This paper sets out CCC metrics and explains how they are computed which leads to guidelines for writing requirements that are measurable.
Simon Wright has a BSc and PhD from the University of London. For 15 years he worked for GECMarconi on various defense projects. He then moved into the commercial software world, initially with the System Modelling tool COSMOS and then with the Requirements Management tool RTM. For the last 13 years he has developed his own client base including the Russian Atomic Energy Authority, Moscow, The European Spallation Source, Lund, Novo Nordisk, Denmark and The Norwegian Army, Oslo. He has been a member of the UK Software Metrics Association for over 10 years. He is an experienced lecturer and has trained many hundreds of people in requirements engineering in a variety of countries. Simon is a good public speaker and has presented at over 30 conferences and seminars, in the UK, the USA and Europe.