USABILITY ANALYZER TOOL: A USABILITY EVALUATION TOOL FOR ANDROID BASED MOBILE APPLICATION

Transcription

1 USABILITY ANALYZER TOOL: A USABILITY EVALUATION TOOL FOR ANDROID BASED MOBILE APPLICATION Abstract: Software usability is very important factor in evaluating the quality of software product and it also affect the success of a project development. There are several area of the software engineering in which we can use the usability as the major constraint like project planning, project construction, software implementation etc. The importance of usability evaluation becomes critical in the early stage of the software life cycle because there are lots of products or applications with similar functionality are available in the market. The scale of on-line markets, users typically face the choice between the applications with similar functionality. Thus developers need to develop high quality application in order to be competitive. In software development, so for the accuracy and efficiency of software usability evaluation is very important in software development. In this paper, we represent some mathematical formulas which effectively and accurately calculate the usability factors. In this paper, we have developed a software usability evaluation tool (i.e. Usability Analyzer Tool ) that helps in software development organizations to calculate the usability factors. The purpose of this paper is to describe a recommended process to develop a tool which measures the software usability for the big organization. These approaches generally followed by the usability evaluation professionals. Keywords: Usability, Human Computer Interaction, Usability factors, Usability evaluation methods, Usability testing of android application, Usability Analyzer Tool. 1. INTRODUCTION Software usability is a major factor in judging the quality of any software or product. The entire software quality model has examined the usability as one of the most significant measure of evaluating the performance of any software. Usability metric is a well known metric to estimate the attractiveness, understand- ability and learnability, operability of the software products and it is a part of software metric. Software metric is a measure of some property of a piece of software or its specifications. Software metrics deals with the measurement of the software product and the process by which it is developed [20]. A software or product is considered usable, if it has a pleasant or acceptable user interface, easy to use and works as our judgement [6]. Usability is a quality attribute of the usage of an application. From the users point of view it can be described as how effectively, efficiently, safe a user can accomplish tasks of a good utility that are Babita Shivade 1, Meena Sharma 2 1,2 DAVV University, IET-DAVV, Khandwa Road, Indore (M.P.), India easy to learn and it can easily to memorize (usability goals). Usability can be enhanced by expert design of the user interface, and, as importantly, by careful design of user system interactions. Usability evaluation is a very essential technique to estimate the function of human-computer interaction (HCI).In HCI we measure the factors which comes during the interaction of computer system. HCI is an interactive system which shows the interaction between human and the computer. Among interactive system developers and users there is now much agreement that usability is an important measure of software systems [1]. Usability is a recent, but sometimes very critical and an abstract idea in human and computer interaction field. According to Jakob Nielsen, usability is defined by the following 5 quality components [23]: Learn-ability: How fast can users learn working with a certain interface and how easy is it for them to do more or less complex tasks when working with the interface for the very first time? Efficiency: How fast are users in accomplishing different tasks once they have internalized the functionality of the interface design? Memorability: When users have not worked with the interface for a longer time, how much of its functionality do they remember and how fast can they regain their proficiency? Errors: Do users make many errors when working with the interface? Are those severe errors and can they easily cope with them? Satisfaction: How satisfied are users after working with the interface concerning the time they had to invest? Was the interface pleasant to use? Software usability evaluation is an approach to estimate the usability for every project or mobile product. Usability metrics included the following factors: efficiency, effectiveness, productivity, satisfaction, learn-ability, attractiveness, operability, accuracy, and response time [2] of every software project. Web based application or software product or even mobile application is needed usability estimation which shows the software usefulness. The proposed tool i.e. Usability Analyzer Tool developed in java, this tool is used to two different purposes, first to calculate the usability of android based application & secondly, to make the comparison between different similar kinds of android application based on Volume 3, Issue 3 May June 2014 Page 247

2 usability criteria. Most of the software's fails due to their attractiveness, understand- ability and learn-ability, operability of the software & so on. Usability metric is a well known metric to estimate the attractiveness, understand- ability and learn-ability, operability, productivity of the software products. For any application or software product, usability is a necessary condition for survival. If a application product or software product is inconvenient to use, people don t want to use that product. If the product fails or discarded, due to their uselessness, so peoples are not interested in that product and people leave. There are lots of similar products available in the market, so usability is very important factor for any software development. According to various user, lost of applications are frequently used in daily life. This makes the usability more important in the application quality. As a result, companies are realizing the advantage of designing and developing products in a usability-oriented manner rather than a purely functionality-oriented manner [8]. 1) First, as the competition is growing on mobile application markets, it s very important for a developer s team to launch their product before competitors release their product. 2) Second, mobile applications are usually developed in comparatively small scale projects which may not be able to support extensive and expensive usability testing. 3) Developer s team are not able to find the root the cause of usability defects, if they perform usability testing after completion of the product. production of mobile applications [14]. Testing methods which measure efficiency, effectiveness, ease of learning and user satisfaction have been developed to take these usability principles into account like Simplicity, Naturalness, Consistency, Efficient Interactions, Forgiveness and Feedback, Effective Use of Language [13]. The usability engineering is an area which deals with the user requirement specification. Generally for evaluating software usability we uses the three following techniques [11]:- 1) Usability Inspection: In Usability Inspection approach, usability-related aspects of a user interface examined by the usability experts and sometimes software developers, users and other professionals. 2) Usability Testing: In Usability Testing approach, firstly we work on the prototype model of the actual system and test it to check whether the system is working as per the user specification or not and also checks the user interface support the users to do their tasks. 3) Usability Inquiry: In Usability Inquiry approach, evaluator observes the users likes, dislike, their needs and understanding about the system through the observation or asking questionnaires. The evaluator note down this interview in written form or store in mind verbally. These usability techniques are also divided into subpart which is summarized in Figure. 1. We have explained the usability analyzer tool is organized as follows. In section I, we explained the introduction. In section II, we present the background and related work.. In section III, we have explained the working of the proposed tool. In section IV, we have explained the usability analyzer tool with experimental results. Finally we conclude the paper in section V. 2. BACKGROUND AND RELATED WORK The purpose of this study is to make the mobile application more familiar with users, because mobile application is used by the common users as well as the technical users. The technical person knows very well how to use application but non technical person don t know. There are lots of mobile applications available in the market which is used for several purposes like calculating, games, alarms, educational purposes etc. So the usability evaluation is the one of the major goal of the software project development process. If the software is more usable than it is used by the lots of users otherwise not. There are various testing strategy available for mobile application like usability testing, compatibility testing, Interface Testing, Services testing, Low Level Resource Testing, Performance Testing, Operational Testing, Security Testing. The important challenges and risks involved in mobile application testing can impact Figure 1 Usability evaluation methods The objective of this tool is to produce the accurate result of software usefulness based on the feedbacks given by real users. In Usability Testing users are given tasks to perform using the product and observed to see if they have any problems performing the tasks. Users perform the tasks on the application that we want to test. Real Volume 3, Issue 3 May June 2014 Page 248

3 users/ programmer(s)/tester(s) should be considered for usability testing. Architecture of the proposed Usability Analyzer tool is given in Figure. 2 Figure 2 Architecture of the proposed Usability Analyzer Tool 3. WORKING OF THE PROPOSED TOOL The proposed evaluation tool (i.e. Usability Analyzer Tool ) represented diagrammatically in figure 2. A Usability evaluation tool enable us to measure the software usability from the real users view points and produce the accurate result of software usefulness based on the feedbacks given by real users. The main perspective of the project can be summarized as follows: 1. Build four android applications for usability testing with the help of ADT. 2. A user uses this application and gives their responses in the form of feedback. 3. This responses store in the databases in the form of numerical values. 4. Then usability analyzer tool fetches this values form the databases 5. Now usability calculation is done based on the certain formula s 6. Now we are able to generate the usability graph also comparison graph for similar type of android application, by which we can show which application is most liked by the user. This tool provides the following usability factors which we are measuring in this project: 1. Effectiveness 2. Efficiency 3. Attractiveness 4. Productivity 5. Response 6. Understand ability 3.1 Usability Evaluation of Android Application For usability evaluation of Android applications, we have considered 4 applications, out of these 4 applications 2 applications are similar and other remaining 2 applications are similar type but there is some difference in their functionality, their appearance as well as their difficulty level. Now we have gone through the usage of all the applications and take the feedback from the evaluator based on some questionnaires and we also generate some logs to evaluate the usability of these four android apps. In usability evaluation of android application we have considered 2 basis method of usability evaluation that is: Questionnaire and Logging which comes under the usability inquiry approach. Questionnaire: In this type of method we asked certain question from the user and they give some answer. This method is very cheap as comparison to other to usability evaluation method. Basically in this method we form or design certain question to take review or feedback from the user and according to this question set we decide the usability of the software. Logging: This method automatically collects all the statistics about the user and the system interaction and the detailed use of the systems. It is very useful because it show the actual use of the system. It contains some log file which records all the data about each event related to every user interface. Typically, an interface log will contain statistics about the frequency with which each user has used each feature in the program and the frequency with which various events of interest (such as error messages) have occurred. In this project we have considered 4 android applications For Usability Evaluation: 1. Alarm Clock 1 2. Alarm Clock 2 3. GK Test 1 4. GK Test 2 There are four parts for each application 1. Usage of an application 2. Feedback Questionnaires 3. Usability Evaluation using Formula's 4. Making Usability Graph and Comparison Graph Usage of an Application In this section basically we describe the usage of an application. All the application which is built in this proposed tool is a general purpose application and their way of usage is similar as the other mobile application, but some differences is there Feedback Questionnaires In this section we will discuss about the feedback question, which we are using for the above all android application. By this feedback question we are measuring the usability of android application which we considered for this project. The entire feedback questions is related to some factor like productivity, efficiency, effectiveness, attractiveness, response time and understand ability. This factor comes under the usability metrics. So with the help Volume 3, Issue 3 May June 2014 Page 249

4 of these questions we finally measure the usability of any software product. These questions are calculated based on some mathematical formulas which we will discuss later on in this report. So the Feedback Question lists are as follows: 1. Is the response time of application satisfactory (Response ) 2. Are the symbols and icons user friendly (Understand-ability) 3. Is the application improving your productivity.(productivity) 4. Is the application interaction user friendly (Attractiveness) 5. Is the design of user interaction help in effectiveness of work (Effectiveness) 6. Is the design of the user interaction efficient.(efficiency) This question is frame in android application which contains 5 options for each question ranging from 1 to 5. 1 means strongly disagree and 5 means strongly agree and 2 to 4 are the intermediate values. The feedback form is shown in Figure.3 Figure 3 Feedback form for android application Usability Evaluation using Formula's In these we will discuss about the usability factors which we are considering in this project. Firstly we will define those factors and secondly how we calculate these factors using certain formulas [3, 15]. 1. Response : What is the time taken to complete the specified task? T= (time of gaining the result)-(time of command entry finished) 2. Understand-ability: Whatever user can understand how to select a software product that is suitable for their intended user and how it can be used for particular tasks. Y=C/D C= Number of user interface functions whose purpose is understood by the user. D= Number of user interface functions 0<=Y<=1, the closer to 1 the better. 3. Effectiveness: The capability of software product to enable users to achieve specified tasks with accuracy and completeness in specified context of use. Eff = 50% Comp + 50% Accu Accu=Accuracy Comp=Completeness 4. Efficiency: The amount of resources expended in relation to the accuracy and completeness with which the user achieves a goal. How user achieve each task efficiently. Efficiency=Task Effectiveness/Task 5. Attractiveness: The capability of assessing the appearance of the software, and will be influenced by factors such as screen design and color. Questionnaire to assess the attractiveness of the interface to users, taking account of attributes such as color and graphical design. Attractiveness=No. of element should be modified/total no. Of element in app 6. Learn-ability: The capability of the software product to enable the user to learn its application. Ease of function learning: How long does the user take to learn to use function? T= Mean time taken to learn to use a function correctly 0<T The shorter is the better. 7. Task : Record how long it takes a user to complete a task in seconds and or minutes. Start task times when users finish reading task scenarios and end the time when users have finished all actions. Task =start time/finish time 8. Productivity: Productivity is the ratio of output to inputs in production.. Development Productivity = Development project size (in Functions) /Development effort (in hours) 3.2 Usability Analyzer Tool In this section we basically show how we are Making Usability Graph and Comparison Graph with the help of Usability Analyzer Tool. All the application has its usability value associated with usability measure. If the organization wants to check the product usability they can check in the form of graph and they can also check the previous result of the particular product and they come to know that which type of usability problems they are facing and how they can improve the product usability. Figure.4 shows the usability graph based on the feedback value getting from the users of any one application and Figure 5 shows the usability comparison graph. All the data which we got from this tool are summarized in the experimental result table which will shown in next section. Volume 3, Issue 3 May June 2014 Page 250

5 When user chooses any one of the above option, value according to particular option is store in database and the calculations perform on these value using formulas. Some of the values already assume constant for calculation. The results for the given android application that we got from the proposed Usability Analyzer Tool are summarized in table I, II, III and IV. Figure 4 Usability Test Result for an android application generated by the tool Figure 5 Comparison Usability Test Result for an android application generated by the tool 4. EXPERIMENT RESULTS In this section we have presented how the proposed Usability Analyzer Tool would be useful to estimate the usability in software as well as estimate the usability of different type of software and the result range of the whole project is ranging from 0 to 1 and calculation has done within this range in the form of: 0<usability factor<1 If usability factor is near to 1 i.e. software or product is more usable, else if it is very close to 0 i.e. software is not more usable, means users are not very much interested in this application. All the usability metrics which we are discussing in this paper like effectiveness, efficiency, productivity, understandability, learn-ability and attractiveness calculated based on formulas. In this project, we have considered 4 android applications this application is used by users and at the end of application they give feedback. Feedback form of an android application is already shown in fig.3. The entire questions have such type of pattern as shown in figure 6. Figure 6 Feedback answer pattern S.n o Table I: Usability Calculated Data for Alarm Clock 1 Effecti ven-ess Efficiency Attract - iveness Under s-tand - ability Respon -se Prod uctivity 1 1.0% 1.0% 0.834% 1.0% 126sec 0.3% 2 0.6% 0.75% 1.0% 0.8% 128sec % 3 0.2% 0.337% 0.166% 0.2% 207sec 0.75% Table II: Usability Calculated Data for Alarm Clock 2 S.no Effectiv en-ess Efficien -cy Attract -iveness Respon -se Under s- tandability Productivity 1 1.0% 1.0% 0.66% 0.66% 80sec 0.375% 2 0.8% 0.8% 0.833% 0.8% 60sec 0.375% 3 0.6% 0.6% 0.833% 1.0% 100sec 0.3% S. no Table III: Usability Calculated Data for GK Test 1 Effec tiveness Efficiency Attractiveness Understandability Response Produ c- tivity 1 1.0% 1.0% 0.833% 1.0% 100sec 0.3% 2 0.8% 1.0% 0.66% 1.0% 60sec 0.3% 3 0.5% 0.625% 0.66% 1.0% 192sec 0.3% S.n o Table IV: Usability Calculated Data for GK Test 2 Effectiv en-ess Efficie n-cy Attract -iveness Understandability Response Produ c- tivity 1 0.8% 1.0% 0.66% 1.0% 60sec 0.3% 2 0.2% 0.333% 0.166% 0.2% 194sec 0.95% 3 0.8% 0.8% 0.833% 0.8% 60sec 0.37% 5. CONCLUSION In this paper we have proposed usability evaluation tool i.e. Usability Analyzer Tool. It is a web based application which evaluates the usability of android application, based on certain usability factors like attractiveness, efficiency, effectiveness, productivity, understandability and response time. It is a very simple tool which calculates the systems usability with the help of formulas. In this system we have selected graph for showing the output because it will be easily understandable. Volume 3, Issue 3 May June 2014 Page 251

6 More specifically, this system is designed for developer as well as the users, who want to test their product usability and also want to compare particular application with other application with similar functionality. Using this software, many organizations can improve their productivity and adaptability of software. It provides a common platform for all the organization and the researcher who wants to work on this area. The advantages of this software are: This tool will facilitate the early detection of usability defects of android apps Since the quality of the software is checked before deploying the software, the quality of the software will be assured So it will reduce development costs as well as maintenance costs. In future, there is scope of increasing the usability factors in this software like satisfaction, accessibility, safety etc. and also there is a scope of getting good result from fuzzy calculation. Other possibilities for adding more android application for usability testing. References [1] Criteria for evaluating usability evaluation methods, H. Rex Hartson1, Terence S. Andre2, and Robert C. Williges2, [2] Usability measurement and metrics: A consolidate Model, Harkirat K. Padda, Ahmed Seffah Mohammad Donyaee,Harkirat K.Padda, Software Qual J (2006) 14: [3] QUIM: A Framework for Quantifying Usability Metrics in Software Quality Models, A. Seffah, N. Kececi, M. Donyaee. [4] Usability-Improving Mobile Application Development Patterns for Android, Bettina Biel, Volker Gruhn, Draft for EuroPLoP [5] Usability Evaluation Of user Interfaces,Inyternational Standard Orgenization, [6] Usability Testing of Android Applications, Aruna Alluri, San Diego State University, 2012 [7] WEBUSE: Website Usability Evaluation Tool, Thiam Kian Chiew and Siti Salwa Salim, Malaysian Journal of Computer Science, Vol. 16 No. 1, June 2003, pp [8] AT-EASE: A Tool for Early and Quick Usability Evaluation of Smartphone Application, Wei Yang, Xiao Yu. [9] The State of the Art in Automating Usability Evaluation of User Interfaces, Melody Y. Ivory And Marti A. Hearst. [10] Evaluating The Usability Of Mobile Applications Without Affecting The User And The Usage Context, Bodo Igler, Tobias Braumann, Stephan Böhm, International Journal Of Business And Management Studies, Vol 5, No 1, 2013 ISSN: [11] Software Usability Evaluation Method,Piyush Jain,Sanjay Kumar Dubey, Prof.(Dr.)Ajay Rana,International Journal of Advanced Research in Computer Engineering & Technology, Volume 1, Issue 2, April 2012,ISSN: [12] A Quality Evaluation of an Android Smartphone Application,Aida Niknejad,Master Thesis in Software Engineering and Management,Report No. 2011:023,ISSN: [13] Defining and Testing EMR Usability:Principles and Proposed Methods of EMR Usability Evaluation andrating,himss EHR Usability Task Force,June 2009 [14] Best Practices in Mobile Application Testing,Mohan Kumar,Manish Chauhan, [15] A Roadmap for Usability and User Experience Measurement during early phases of Web Applications Development,Muhammad Arslan, Muhammad Assad Riaz, Master Thesis Software Engineering, Thesis no: MSE ,April [16] A Toolkit for Usability Testing of Mobile Applications,X. Ma, B. Yan, G. Chen, C. Zhang, K. Huang and J. Drury. [17] Critical Evaluation On Software Development Process Models With Respect To Mobile Software Development,Kesava Pillai Rajadorai, Sa adah Hassan and Novia Admodisastro, [18] Selecting a Mobile App: Evaluating the Usability of Medical Applications,mHIMSS App Usability Work Group,July [19] On Performance of Mobile Systems: Challenges of Software Design and Evaluation,Vahid Rahimian, Jafar Habibi,v1. [20] Software Metrics,Everald E. Mills,SEI Curriculum Module SEI-CM ,December 1988 [21] Executive Summary, in Usability Inspection Methods, R. L. Mack and J. Nielsen,New York, John Wiley & Sons, [22] Using Protocol Analysis to Evaluate the Usability of a Commercial Website,R. Benbunan-Fich,in Information & Management, Vol. 39, No. 2, 2001, pp [23] Nielsen, J. Usability 101: Introduction to Usability.. tml Volume 3, Issue 3 May June 2014 Page 252