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User-centered design process step 2: Usability metrics

Editor’s Note: This blog series provides readers an inside look at how members of our user experience team approach new projects. As they go through the design process for a specific solution, they’ll share how they use science and a rigorous process to create a better experience for our users. This is the second post in a four-part series.

In my previous blog, we talked about understanding the user and how we use knowledge of how humans perceive, think, decide and respond to create designs that decrease the cognitive load for users and reduces their burden.

Once you understand what the user’s objectives are, the next step in a User-Centered Design (UCD) process is to determine what will make the design succeed from a usability standpoint by creating measurable usability goals (or usability metrics).

These are specific goals covering areas you want to improve as a result of the design. The product is measured throughout the design process to ensure that the final design meets the expectations of the user and helps them achieve their objectives efficiently.

Usability goals can be measured in a variety of ways throughout the project, including the use of surveys, observation during user testing and the use of third-party tools such as predictive human performance indicators.

When setting usability goals, we ensure that each one has a clear and measurable outcome. First, we determine how the goal will be measured and the target outcome for the goal.

For this project, we created goals to measure three things: can the user complete key tasks, did we increase efficiency for the user, and did we meet the user’s perception of the product.

Prescription writer task-based goals

The first group of the usability metrics are designed to measure whether users can easily perform certain tasks within the new design. These will be measured objectively during the usability tests by asking users to complete the tasks without being taught how to use the product. These metrics are designed to ensure that changing the interface will not cause major disruption for existing users and will not require hours of training for new users. For all of these metrics, the goal is that 100% of users can complete the task by the second attempt (with a minimum acceptable goal of 80% of users who can complete the task by the second attempt).

The metrics that we set for this category include:

  • The user understands how to access each part of the application via the high-level navigation model (medication list, Add/Edit prescriptions, filters, search, etc.)
  • The user can identify the formulary status of medications
  • The user can Complete a new prescription
  • The user can Add a prescription for a compounded medication
  • The user recognizes when an extra step is required for a medication (PDMP, prior authorization, price point transparency, etc.)
Increased efficiency while using prescription writer

Increasing the efficiency for the provider is really important to ensure they can focus on their patients instead of the system. For this project we decided to focus on reducing the amount of time spent on particular tasks. This can be measured either by using a predictive human performance indicator tool (such as CogTool or Cogulator) or by actually timing the same user performing the task on both systems. For both of these metrics, the goal is to reduce the task time by 30% over the current application (with the minimal acceptable criteria being that the new design at least meets or improves the task time of the current application).

The metrics that we set for this category include:

  • Improve the efficiency of the application for searching and selecting a medication
  • Improve the efficiency of the application for completing a prescription form
User’s perception of the prescription writer

It is possible to meet the criteria above and still not meet the expectations of the user. For our final set of usability metrics, we focus on the user’s expectations and whether we meet what they expect for a prescription writer. These metrics are measured using surveys, with both a survey of the existing product and a survey of the design being completed. For all but the System Usability Scale (SUS), the goal for these metrics is a score of four on a five-point scale (with the minimal acceptable criteria being that the new design at least meets or exceeds the current product rating). The goal for the SUS is a score of 70 (with the minimal acceptable criteria being that the score on the new design at least meets or exceeds the score of the current application).

The metrics we set for this category include:

  • The application helps the user prescribe medications safely
  • The application helps the user prescribe medications quickly
  • Appropriate information displays at the appropriate time
  • The terminology used in the app meets user expectations
  • The application looks “new” and “fresh”
  • The application gives the user a sense of satisfaction and is perceived to be easy to use (SUS Score).

These usability goals will be used as we test and refine the designs for the product which will be covered in future blog posts.

In the next blog, I will cover step three of the UCD process: Patterns and standards. View the previous blog post here.

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