Software Project Management Lecture # 11

Outline Quality Management (chapter 26 - Pressman)  What is quality?  Meaning of Quality in Various Context  Some quality concepts  SQA – activity summary

What is Quality? British Standard Institute’s definition  Quality is totality of features & characteristics of a product or service which relate on its ability to satisfy a given need American Heritage Dictionary definition  Quality is characteristic or attribute of something Quality of Software  Quality of Software is software that does what it is supposed to do – customer dissatisfaction is lack of quality

Meaning of Quality in Various Context In manufacturing  Quality means that the developed product should meet its specification In software development  Quality would mean that a software product conforms to its specification Software specification should be oriented towards customer requirements. There may be some implicit requirements like maintainability, usability, etc. but they are not included in the specification

Meaning of Quality in Various Context Practically, its very difficult to write complete software specifications/ characteristics Therefore, although the product conforms to its specifications, it may not satisfy the customer as hence may not be considered as a high quality product

Another school of thought … Quality can achieved by defining standards & organizational quality procedures that check that these standards are followed by the software development team Besides standards & procedures there are intangible aspects also involved in software quality like elegance, readibility, etc.

Quality Concepts Quality of design  Refers to the characteristics that designers specify for an item  Focuses on requirements, specifications & design of system Quality of conformance  Is the degree to which the design specifications are followed during manufacturing  Focuses primarily on implementation User satisfaction  Complaint product + good quality + delivery within budget & schedule

Quality Concepts Quality Control  Definition & enhancement of processes that ensure the software development team has followed project quality procedures & standards  Quality Control is a series of inspections, reviews & tests used through out the development cycle to ensure that each work product meets the requirements placed on it  It includes feed-back loop to the process that created the work product  The combination of measurement & feedback helps to fine tune the process when work products fail to meet their specification

Quality Concepts Quality Assurance  The process of defining how software quality can be achieved & how the development organization knows that the software has the required level of quality  It involves establishment of a framework of organizational procedures & standards that lead to high quality software  It consists of a set of auditing & reporting functions that assess the effectiveness of quality control activities.  The aim is to provide management with facts & figures and proofs that product quality is meeting its goals

Quality Concepts Variation Control  Variation control is the heart of quality control  Variation control may be equated to quality control  Manufacturers aim to minimize the variation among the products that are produced  For software projects, from one project to another, we may want to minimize the difference between predicted resources needed to complete project and actual resources used, including staff, equipment, and calendar time

Quality Concepts Cost of Quality  It includes all costs incurred in performing quality related activities  Cost of quality studies are conducted to Provide a baseline for current cost of quality Identify opportunities for reducing cost of quality Provide normalized basis of comparison (usually in dollars)  Quality costs are divided into Prevention costs Appraisal costs Failure costs

Quality Concepts Quality costs  Prevention costs relate to Quality planning Formal technical reviews Test equipment training  Appraisal costs relate to Activities to gain insight into product – “first time through” each process, e.g.,  In-process and inter process inspection  Equipment calibration &maintenance  testing

Quality Concepts Quality costs  Failure costs Those that would disappear if no defects appeared before shipping a product to customer Failure costs subdivided into 2 types  Internal failure costs (related to defects found before product is shipped) Rework, repair & failure analysis mode  External failure costs (related to defects found after product is shipped) Complaint resolution, product return and replacement, helpline support & warranty work

Relative cost of correcting an error  Refer to figure 26.1

SQA – Activity Summary SQA is an activity that is applied throughout the software process and not after the software has been developed SQA covers the following  Quality management approach  Effective s/w engineering technology (methods & tools)  Formal technical reviews (applied throughout the process)  A multi-tiered testing strategy  Control of software documentation & changes made to it  A procedure to assure compliance with software development standards  Measurement & reporting mechanism Refer to pg. 750 for details