Impact of user satisfaction on Software quality in use

Transcription

1 International Journal of Electrical & Computer Sciences IJECS-IJENS Vol: 11 No: Impact of user satisfaction on Software quality in use Tayyaba Nafees BS (CS) Institute of Computing, Department of Computer Science Bahauddin Zakariya University Multan,Punjab, Pakistan Abstract The idea of user satisfaction is not new. But how important it is in quality in use is new and under description. Satisfying the customers is an essential element to staying in business in this modern world of global competition. Software companies satisfy and even delight their customers with the value of their software products and services to gain their loyalty and repeat business. Customer satisfaction is therefore a primary goal of process improvement of software quality. Most of the software companies give the more importance to user satisfaction rather than McCall other quality factors. So in this paper I argue about the quality in use and user satisfaction, its relationship and its importance. Keywords User satisfaction; quality in use; metric. 1.Introduction Many definitions of software quality have been published, which in general agree on what quality means and their agreement can be preserved by the phrase satisfaction of customer requirements. In simple language, software must do what the customer expects it to do. The customer plays an important role in software quality. The international standards ISO9000 [7], [8] IEEE [9] and Baldrige[10],[12] place emphasis on customer perceived quality and expect that customer satisfaction be strongly linked to all functions of a business. Quality as the totality of characteristics of an entity that bear on its ability to satisfy stated and implied needs. ISO (1994) ISO DIS 8402: Quality Vocabulary. Garvin defines User perceived quality as the combination of product attributes which provide the greatest satisfaction to a specified user. [6] The proposition of ISO/IEC 9126 is that higher external quality (quality when software is executed) indicates higher quality in use. Sub characteristics of external quality are of little value by themselves unless there is empirical evidence that they are associated with important characteristics such as user satisfaction, defined in quality in use. [3] Quality in use as a construct is defined as the capability of the software product to

2 International Journal of Electrical & Computer Sciences IJECS-IJENS Vol: 11 No: enable specified users to achieve specified goals (ISO/IEC ). Quality in use is the user's view of the quality of an environment containing software, and is measured from the results of using the software in the environment, rather than properties of the software itself. The competitive environment in the software market and the needs of customers require that software developers focus on user satisfaction as a measure of software product quality. User Satisfaction is often considered as the ultimate aim of quality management and has a positive impact on organizational cost, profit, and sales growth [1]. Investigation of the quality attributes that influence user satisfaction requires the use of a quality model. A quality model normally defines a set of quality attributes that may be present in software product. In particular, because users place different [2, 11, 29] Product quality Manufactu ring quality Quality User perceived quality Economic quality Rather than debate which (if any) of these definitions of quality is correct, they should be recognized as distinctly different approaches, each of which has value for its own purpose. But our main concern is about the user perceived quality. 2. USER PERCEIVED QUALITY AND QUALITY IN USE Garvin defines User perceived quality as the combination of product attributes which provide the greatest satisfaction to a specified user. 2.1Quality as user satisfaction The ISO/IEC 9126 definitions acknowledge that the objective is to meet user needs. But ISO 8402 makes it clear that quality is determined by the presence or absence of the attributes, with the implication that these are specific attributes which can be designed into the product. For software, they would thus be attributes of the source code. When combined with an ISO 9001 compliant quality process, the most natural interpretation is that quality should be specified and evaluated at the level of source code attributes.iso 8402 distinguishes this view of quality from measures of the degree of excellence resulting from the presence or absence of required attributes. Yet the objective of quality from the user s perspective is for the software to exhibit excellence in the actual conditions of use.

3 International Journal of Electrical & Computer Sciences IJECS-IJENS Vol: 11 No: SOFTWARE QUALITY IN USE: ISO The users needs can be expressed as a set of requirements for the behavior of the product in use (for a software product, the behavior of the software when it is executed). These requirements will depend on the characteristics of each part of the overall system including hardware, software and users. The requirements should be expressed as metrics which can be measured when the system is used in its intended context, for instance by measures of effectiveness, efficiency and satisfaction. At this level, the required system characteristics could be minimum values for the effectiveness, efficiency and satisfaction with which specified users can achieve specified goals in specified environments. [5] 3. MEASURING QUALITY IN USE Quality in use is the user s view of the quality of a system containing software, and is measured in terms of the result of using the software, rather than properties of the software itself. Quality in use is the combined effect of the software quality characteristics for the end user. It can be measured by the extent to which the specified users can achieve their goals with effectiveness, task efficiency and satisfaction. Effectiveness can be measured by the accuracy and completeness with which users achieve specified goals, task efficiency by the resources expended in relation to task effectiveness, and satisfaction by attitudes to the use of the product. Examples of metrics for quality in use are given in ISO/IEC

4 International Journal of Electrical & Computer Sciences IJECS-IJENS Vol: 11 No: The objective of designing and evaluating for quality in use is to enable users to achieve goals and meet needs in a particular context of use. ISO explains how quality in use can be measured in terms of user performance and satisfaction: by the extent to which the intended goals of use are achieved, the resources that have to be expended to achieve the intended goals, and the extent to which the user finds the use of the product acceptable. ISO emphasizes that quality in use is dependent on the context of use and that the level of quality in use achieved will depend on the specific circumstances in which a product is used. The context of use consists of the users, tasks, equipment (hardware, software and materials), and the physical and social environments which may all influence the quality in use of a product in a working environment. Measures of user performance and satisfaction assess the quality in use of a product in the particular context of use provided by the rest of the working environment. Specifying and measuring the quality in use of products In order to specify or measure quality in use it is necessary to decompose effectiveness, efficiency and satisfaction and the components of the context of use into sub-components with measurable and verifiable attributes. The components and the relationships between them are illustrated in figure 2[16] 3.1Information needed When specifying or measuring quality in use, the following information is needed: A description of the components of the context of use including users, equipment, environments, and tasks. This may be a description of an existing context, or a specification of intended contexts. The relevant aspects of the context and the level of detail required will depend on the scope of the issues being addressed. The description of the context needs to be sufficiently detailed so that those aspects of the context which may have a significant influence on quality in use could be reproduced; Quality in use measures consisting of target or actual values of effectiveness, efficiency, and satisfaction for the intended contexts. The specification or measurement of the quality in use of a particular product should identify the overall goal of the user, specific sub-goals, the relevant context of use, including the tasks and resources involved, and the measures of effectiveness, efficiency and satisfaction which are chosen as being relevant to the goals which have been identified.

5 International Journal of Electrical & Computer Sciences IJECS-IJENS Vol: 11 No: Figure 2: Quality in use framework 4. User satisfaction is key of quality in use The purpose of designing an interactive system is to meet the needs of users: to provide quality in use (Bevan, 1999). The internal software attributes will determine the quality of a software product in use in a particular context. Software quality attributes are the cause, quality in use the effect The users needs can be expressed as a set of requirements for the behaviour of the product in use (for a software product, the behaviour of the software when it is executed). These requirements will depend on the characteristics of each part of the overall system including hardware, software and users. The requirements should be expressed as metrics that can be measured when the system is used in its intended context. The

6 International Journal of Electrical & Computer Sciences IJECS-IJENS Vol: 11 No: required system characteristicss could be minimumm values for the effectiveness, efficiency and satisfaction with whichh specified users can achievee specified in specified environments.[13] goals Figure 3: Quality in the software lifecycle [13] 4. Software metrics Software metrics deals with the measurement of the software product and the process by which it is developed [15] software metric Quality in use metrics user staisfaction metric 4.1Quality in use metrics Quality in use is the user s view of the quality of a system containing software, and is measured in terms of the result of using the software, rather than properties of the software itself. Quality in use is the combined effect of the software quality characteristics for the user. This broad view of quality has traditionally been the province of ergonomics, which is concerned with the factors in the physical

7 International Journal of Electrical & Computer Sciences IJECS-IJENS Vol: 11 No: and social environment which influence the extent to which people can achieve their goals. All these elements of the work system determine how people behave and whether they are successful in their tasks. The output of the work system can be measured as effectiveness, productivity, and satisfaction of the users (Figure 4). they are FURPS (functionality, usability, reliability, performance, and service) [17]. On the basis of the five point scale data, a lot of quality metrics can be constructed and used, depending on the purpose of analysis. For example: 1) Percent of completely satisfied customers 2) Percent of satisfied customers (satisfied and completely satisfied) 3) Percent of dissatisfied customers (dissatisfied and completely dissatisfied) Fig 4: Quality in use ISO/IEC User Satisfaction Metrics User satisfaction is often measured by customer survey data via the five-point scale [17]: Very satisfied Satisfied Neutral Dissatisfied Very Dissatisfied. Satisfaction of user or customer with the quality of product can usually be determined by performing surveys of customers. For example, the specific parameters of customer satisfaction in software monitored by IBM include the CUPRIMDSO categories (Capability, Functionality, Usability, Performance, Reliability, Install ability, Maintainability, Documentation, Service, and Overall); for Hewlett Packard 4) Percent of non-satisfied ( neutral, dissatisfied, and completely dissatisfied) Primary focus of developers is on the reduction of faults and improvement of the quality of product delivered, which means increase of satisfied customer and decrease of nonsatisfied customers. For this purpose normally the second metric, percent satisfaction is used [17]. In addition to forming percentages for satisfaction or dissatisfaction metrics, the weighted index approach can be used. For instance, some companies use the Net Satisfaction Index (NSI) to facilitate comparisons across product. The NSI has the following weighting factors [17]: Completely satisfied = 100% Satisfied = 75% Neutral = 50%t Dissatisfied = 25% Completely dissatisfied = 0%

8 International Journal of Electrical & Computer Sciences IJECS-IJENS Vol: 11 No: Conclusion So quality in use represents the extent to which the software product meets the actual operating needs of the customer. Quality in use becomes a more permanent driver of customer satisfaction as the customer begins to routinely use the software.[14] The primary measure of quality in use comprise the quantification of the benefit of the product to the user(bevan 1999).At the end I only says that quality in use is directly depend on the user satisfaction. 6. Reference [1] C.N. Madu, C.H. Kuei, R.A. Jacob, An empirical assessment of the influence of quality dimensions on organizational performance, International Journal of Production Research 34 (7) (1996) [2] B. Boehm, Identifying qualityrequirement conflicts, IEEE Software 13 (2)(1996) [11] R.G. Dromey, A model for software product quality, IEEE Transactions on Software Engineering 21 (2) (1995) [29] J. McCall, P. Richards, G. Walters, Factors in software quality, NTIS ADA ,-15, 055, [3] Validating the external quality sub characteristics of software products according to ISO/IEC 9126 By Ho-Won Jung [4] Journal of System and Software, 1999 (in press) Quality in Use: Meeting User Needs for Quality Nigel Bevan Serco Usability Services [5] Quality in use: incorporating human factors into the software engineering lifecycle by Nigel Bevan National Physical Laboratory Division of Information Technology and Computing Teddington, Middlesex, TW11 0LW [6]Garvin (1984) What does "product quality" really mean? Sloane Management Review, Fall [7]ISO, Quality Management and Quality Assurance Standards, International Standard, ISO/IEC 9001: 1991 [8]Ince, D, ISO 9001 and Software Quality Assurance, Quality Forum, McGraw Hill, isbn: , 1994 [9]IEEE, Standard for a Software Quality Metrics Methodology, P- 1061/D20, IEEE Press, New York, 1989 [10]Brown, M G, Baldrige Award Winning Quality: How to Interpret the Malcom Baldrige Award Criteria, Milwaukee, WI: ASQC Quality Press, 1991 [12]Steeples, M M, The Corporate Guide to the Malcom Baldrige National Quality Award, WI: ASQC Quality Press, 1993 [13]ISO/IEC (1998) Information Technology - Evaluation of Software Products - Part 1 General guide. [14]Safe and sound software: creating an efficient and effective quality system... By Thomas H.Fari,UK

9 International Journal of Electrical & Computer Sciences IJECS-IJENS Vol: 11 No: [15] Software Metrics SEI Curriculum Module SEI-CM December 1988 by Everald E. Mills,Seattle University [16] ISO (1996) ISO DIS Ergonomic requirements for office work with visual display terminals (VDT)s Part 11 Guidance on usability. [17] Stephen H. Kan (2002) Software Quality Metrics Overview [Online] 2nd ed. Boston: Addison Wesley Professional. Available from: < icle.asp?p=30306&seqnum=6&rl=1> [Accessed July 25, 2007]