Usability Engineering Lifecycle Model

Introduction

The Usability Engineering Lifecycle (UEL) model has three phases: requirement analysis, design/testing/development, and installation. Each phase has a different set of activities that must be covered to get the best out of the design process. Let’s take a brief look at each of the phases.

Phase 1: Requirements analysis

Requirement analysis is the study of users and their needs, required tasks, and defining usability guidelines for the system. This phase involves four tasks:

• User profiling: This involves identifying user characteristics, requirements, and the problems they are facing with current software. For example, if a person has tremors, mouse sensitivity should be lowered.
• Contextual task analysis: This involves identifying the current user tasks, work environments, and workflow patterns. This analysis helps to understand user behavior towards current applications and how the user will respond to your design. For example, if a system is to be used in a highly interruptive environment where users are likely to get distracted, then the system should be able to provide constant feedback to let the user know what has been done, what they are doing, and what the next task is?
• Usability goal setting: This involves setting specific, qualitative, and measurable goals for the requirements we concluded on during user profiling. For example, a novice user should not take more than 40 seconds to sign up for the system account.
• Platform capabilities and constraints: This involves addressing system or interface capabilities and constraints while specifying usability goals. The usability goals should be consistent with the platform possibilities, i.e. a goal that a user should perform a specific task in a specific amount of time will never be met if the platform takes more than the specified time to process.
• General design guidelines: This involves specifying general design guidelines for the interface design. For example, if the interface has a form, then use guidelines to make that form useable as well as beautiful.

Phase 2: design/testing/development

This phase is subdivided into three levels of work. It starts with designing a simple model derived from the requirements decided in user profiling and ends with a complete working product.

Level 1 design

Level 1 is the development of conceptual design. System functions, rules, and workflow are designed at this level.

Note: The more information you collect in phase 1, the more user input you will be able to incorporate into the design. This increases your design’s chances of getting accepted by the users.

This level includes four tasks. Let’s study each.

• Work re-engineering: This involves the theoretical organization of functions, tasks, and workflows. This task does not involve any interface design work and it should be completed before starting design.
• Conceptual model design: This involves determining high level design rules for product interaction with the user and information representation. If the product is extremely simple and does not require complex mechanisms for prototyping and evaluation, then the design team can skip the rest of the tasks and move directly to level 2 design. This flow is represented by a dotted line in the image below.
• Conceptual model mockups: This involves creating low-fidelity prototypes of the conceptual designs. The first prototype can be a simple paper or a wireframe design created using any prototyping tools.
• Iterative conceptual model evaluations: In this step the prototype finalized from the previous task is evaluated by the team. This is an iterative process. If a major flaw is identified in the prototype, the design moves to the first task, which is work re-engineering. The prototype then gets modified. This cycle is repeated until all major flaws are identified and eliminated. Once the model is finalized, it is documented in the style guide and distributed among team members.

Level 2 design

When the conceptual model has been constructed successfully, the next task is to define standards for the product.

Note: Defining standards is a very important step as these standards will be followed by the design team. This way each team member has the same standards, which helps avoid design conflicts

This level comprises three tasks. These tasks are as follows:

• Screen design standards: This involves defining interface specific standards and rules that will be followed through the process. If the product standards are fairly simple and do not require prototyping and evaluation, then the design team moves directly to level 3.

• Screen design standards prototyping: During this step, the defined standards are applied to the product to test how the system looks and performs.

• Iterative screen design standards evaluation: Finally, the standards are evaluated and refined mainly based on usability testing. If the usability goals we defined in the first phase are met, then the standards are documented in the style guide and the team moves on to the third and last level. Otherwise, the cycle repeats until all major usability issues are resolved.

Level 3 design

After all the work and preparation required in the previous levels have been completed, the next task is to actually design the product, i.e. implementation. This level has two tasks to complete.

• Detailed user interface design: In this task, the design team follows the style guide to implement the product. The resulting product is the beta versionThe product version that is made available to a limited number of users and testers to test the product before actual release..

• Iterative detailed user interface design evaluation: Once, the beta testing is done and feedback is incorporated, the design team conducts a final design usability evaluation to remove any usability issues. The cycle repeats until all goals are met and the final product design details are documented in the style guide.
  Once the product is finalized, the product is evaluated to make sure all required functions have been implemented. If the team finds any unaddressed functions, it means that the requirements were not gathered properly. If this is the case, the cycle is moved back to the very first phase of the useability engineering lifecycle model.

Phase 3: Installation

The last phase is the deployment of the product and includes a “never-ending cycle” of user feedback incorporation. This phase has two tasks.

• Installation: In this task, the product is installed and made available for the users. Over a period of time, users use this product and submit feedback. The feedback can include appreciation and complaints regarding the product’s functionality.

• User feedback: The submitted feedback is reviewed by the design team and necessary changes are made to the product. If all the issues are resolved, we are done with the design cycle. Realistically, this cycle never actually ends. Chances to receive new feedback remain even after the product is live. A new user issue can arise anytime, and the cycle gets repeated.

The UEL model

You can see a graphic of the entire process below.