Changes between Version 46 and Version 47 of CoreLibrary/UsabilityAnalysis
- Timestamp:
- 10/25/12 14:25:49 (12 years ago)
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CoreLibrary/UsabilityAnalysis
v46 v47 3 3 = Usability Analysis = 4 4 5 AutoQUEST provides support for analysing the usability of a software. For this, it can be provided with recorded or manually created us er sessions. AutoQUEST transforms them into task trees and analyses them for known usability problems. As an example, a user may click three buttons of a user interface always in the same order. Ashe has to click three buttons, this is less efficient than clicking only one button that comprises the functionality of clicking the three buttons. AutoQUEST detects this and proposes to combine the three buttons to one. The following sections provide more details.5 AutoQUEST provides support for analysing the usability of a software. For this, it can be provided with recorded or manually created usage sessions. AutoQUEST transforms them into task trees and analyses them for known usability problems. As an example, a user may click three buttons of a user interface always in the same order. As she has to click three buttons, this is less efficient than clicking only one button that comprises the functionality of clicking the three buttons. AutoQUEST detects this and proposes to combine the three buttons to one. The following sections provide more details. 6 6 7 = Software Usability = 8 Software supports its users in conducting their tasks. This is independent of the type of users. A user can be a human or another software. If a software allows its users to conduct their tasks with effectiveness, efficiency, and (in case of humans) satisfaction, it has a good usability. 7 == Generating Usage Models == 9 8 10 As an example, you can think of the different tools of an office suite. Such usually provide a tool for writing documents and another one for creating presentation slides. With both tools, you may create a poster. Therefore, they both support conducting the same task. When doing the layout of the contents of the poster, both tools provide different mechanisms for doing so. While the tool for writing documents supports the usage of text columns and images anchored on the page, the presentation tool directly allows laying out the elements using appropriate boxes. For many users, using the second variant is much more efficient and satisfying. Therefore, the presentation tool has a better usability for creating posters with respect to the mentioned users. In addition, another tool that is directly designed for creating posters may provide an even better usability. 9 The first step of AutoQUEST usability analysis is the creation of usage models. Usage models can describe the interactions of a user performed on a GUI as well as calls to an API. The simplest usage model is a sequence of elementary actions. An action is, e.g., clicking with a mouse or pressing a key on the keyboard. A combination of several actions form a task. As an example, the task of entering a word into a textfi 10 eld is a combination of actions, such as clicking on the textfi 11 eld and pressing and releasing keys. 12 Tasks and actions can be combined to form a higher level task. For example, the task of fi 13 lling out a form presented by a software is made up of several tasks for entering values into textfi 14 elds and a 15 final click on a confi 16 rmation button. Furthermore, the task of 17 filling out the form can be part of another higher level task. Therefore, we organize the tasks in task trees. 11 18 12 = Usability Engineering = 19 A task tree is a structure for a task that a user or another system performs with a software. It decomposes a task into subtasks, which can be further subdivided. Each task and its subtasks are represented as nodes in the task tree. The leaf nodes of a task tree represent the actions a user must perform to fulfi 20 ll the overall task. The subtasks of a parent task are set into temporal relationship. This de 21 fines the order in which they must be executed to ful 22 fill the parent task. 13 23 14 Usability should be considered throughout the whole software development process. For this, a broad variety of methods exists that can be used at distinct stages of the process. Most of these methods assess the state of the usability the user interfaces. They can even be used for unfinished blueprints of the user interfaces. Applying such methods in the development process is referred to as usability engineering.24 The input for generating task trees in AutoQUEST are sequences of elementary actions. Those can be manually defined or recorded using the monitors provided by AutoQUEST. AutoQUEST then combines actions that logically belong together into tasks. For example, it creates a task for all interactions that took place in the same panel of a GUI. In a next step, AutoQUEST identifies iterations of task. Finally, AutoQUEST identifies selections between different tasks that a user can choose from at a specific point in the interaction. The result is a condensed task tree, that shows all possible interaction combinations. 15 25 16 Most of the methods of usability engineering rely on a proper analysis of the application context. With an increasing size of the application context, such as a larger number of different users, the analysis becomes imprecise. This causes a decrease of the achievable usability for the individual user or a group of users. Furthermore, the users that are actually using the software as well as their way of using the software may differ from the expectations of an initial user analysis. This is because users very often use software also for tasks, for which it was not implemented. As an example, many posters nowadays are created using tools for screen presentations or writing documents as poster software is either rare or expensive.26 The task tree model is not fully correct, as the analysed sequences do not contain all possible interactions. However, it provides sufficient information to perform a usability analysis for the concrete interaction sequence that was analysed. 17 27 18 = AutoQUEST and Usability Analysis=28 == Generating Interface Models == 19 29 20 AutoQUEST analyses the usability of a software for the users that are using it. For this, it records users while using a software for their tasks. Based on this recording, AutoQUEST provides tools for usability analysis. At the first step, these tools determine a model of the usage of a software. This model is a task tree that combines the individual user interactions to logical units. Furthermore, AutoQUEST is able to determine a model of the GUI of the software. Based on both models, AutoQUEST is capable of performing a usability analysis of the software. As an example, a task tree may contain a regularly repeated list of user interactions on specific elements of the GUI. For most effective support for the user, these GUI elements should be colocated. If they are colocated can be checked using the GUI model. The outcome of AutoQUESTs usability analysis is a report indicating potential usability defects with an estimation for their severity and a detailled description.30 For its subsequent usability analysis, AutoQUEST requires a model of the user interface. This is determined based for the interaction sequences. The interaction sequences contain the interactions that took place as well as the interface elements that were used. The latter one are extracted and combined to an interface model. 21 31 32 == Analysing Usability == 33 34 To assess the usability of a software, AutoQUEST first analyses the generated task trees. Those show initial usability issues. As an example, a task tree should not contain too many iterations, as users should not be forced to iterate something. Furthermore, a task should not be split up into too many subtasks that have to be executed in exactly one sequence. Users usually have problems in performing more than 7 steps in a specific order to achieve a goal. 35 36 In a next step, the usability analysis also includes the interface model. As an example, AutoQUEST may detect, that most interactions of the user are done on text fields. This may be OK for very specific applications, but usually, it is much more easy for users to enter data using GUI elements like date choosers, combo boxes, etc. Therefore, AutoQUEST also identifies potential of improving the interaction design of a user interface.
