Tuesday, March 30, 2010

Know What Thy User Does and Where They Do It

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Last time, I discussed the importance of knowing your target population and their use environment. That first step identifies and specifies the population for inclusion. It is the means for including who should be included and excluded, and the environment where they work. For example, a targeted population for a particularly medical product could be surgical nurses who work in hospitals. The target population does not include all nurses or even all surgical nurses. In addition, the use environment in which the targeted population performs their work needs to be a part of the definitional equation.
Thus, the first step in the design process is defining the properties of the target population, determining who is and who is not part of that population. And include a complete description of their working environment, the environment where the product or service will be used. Field research will be necessary to establish the target population and its characteristics and the work environment. When this step is finished, the next step is perform additional research to establish the details of the work of interest and the environment in which it performed. (The means for collecting this information and form of the analytic product will be discussed in a later article.)

Know What Thy User Does and Where They Do It
Knowing what the user does consists of documenting the tasks that the target user population would perform with the product or service that a company plans to provide.

Once the product or service has been conceptually defined, the following information from the target population must collected:

  1. The preconditions that lead to performing each task,

  2. The steps required to perform a task, and

  3. How frequently each is performed (in absolute terms and in relationship to other tasks.

The information collected focus on the actions performed by a user localized to the product or service in development. The data would have little or no reference to the use environment – the full set of activities and environmental conditions wherein this product or service will be used. Thus once having collected the task data specific to the product or service in development, the next step would be placing this product or service within the environment wherein it will used.

A full and complete description or representation of the use environment may not always be possible. Moreover, often times there are multiple use environments. And a description or descriptions may be only of a representative sample. Nevertheless, it can be extremely useful to understand how the product or service in development will be used in context.
The final research products resulting from this step in the product development process are:

  1. Task analyzes: pertaining only to the product or service in development.
That include:

  • Breadth analysis, that consists of:

  • The number of tasks users would perform using the product or service in development

  • Their frequency of performance

  • Depth analysis

  • Define how each task is performed

  • The level is detail required will vary with the complexity of the task

  • Each task analysis should include likely errors and the steps required to correct them.

  • There are a variety of means to represent task analyze. The representation method should be agreed on by the affected parties.

  1. Task execution within the wider use environment

  • The tasks that users will perform with the product or service in development will be performed within a larger context.

  • The tasks within the wider context and how those other tasks relate to each other requires documentation.

  • The other tasks require a breath analysis. Rarely is a depth analysis required unless tasks are intermingled.

I discuss the benefits of knowing what your user does and where they do it in my next article. I shall discuss with reference to HE75 and what the FDA will likely require from the medical product companies.

Where in a company's organizational structure is this work performed?

Knowing your 1) target population and their use environment, and 2) what your users do (task analysis) are the first two steps in the product formation stage of development. This precedes requirements gathering stage of product development. Thus, this would require the engagement of human factors engineers working with marketing and other product and field-focused organizations to engage those working at this early stage. St. Jude Medical with whom I consulted for 15 months has placed their all their human factors engineers in systems engineering. Thus, the placement of human factors engineering only in systems engineering means that important data impacting the beginning of product development is either not produced, or produced at a later stage in the development process where its impact is minimal or non existent.

As I shall discuss later, it is important that human factors engineering be involved from concept to deployment, thus human factors engineers should be distributed throughout an organization.

Stirrings in the Regulatory Environment

Medical product producers are regulated by the Federal Government. Anyone who reads this blog is highly likely to know that. Drug companies are acutely aware of governmental regulation in that their products must be “safe and effective.” Drug companies must prove through research safety and effectiveness. Implanted device manufacturers must demonstrate that the implanted devices themselves are safe and effective. Devices and drugs that deliver therapy have to prove to the FDA safety and effectiveness.

But what about the user interfaces for devices that enable users to make changes to the operation of implanted devices, deliver therapies, provide information about the patient, etc., where's the proof in the form of empirical data to prove that they're safe and effective?

In the US, more people are killed by medical errors each year than are killed in automobile accidents and in the military service combined. Yet, the FDA has placed few relatively requirements on the process for designing user interfaces on medical products and services. This is a disgrace and the FDA knows it. FDA mandates for insuring the usability of medical devices, products and services has been merely to determine only that a usability process is in place. FDA mandates for usability have not reached the level of the Departments of Defense or Transportation. Companies that design and build medical systems have not been required to prove to the FDA that their products are usable in their use environment. Yet, it is clear that usability is just as important in medical practice as with combat systems and cars – particularly when one considers the number of injuries and deaths resulting from medical errors. And with more powerful and complicated systems are being designed and planned, the need for the FDA to act and act effectively in the area of usability grow substantially.

In my personal experience, I saw a device under development that if used improperly, could injure or in one case, lead the to death of a patient. In fact, I uncovered a condition in which the device when used properly could lead to death. And, it would have been surprisingly easy to do. Of course, I raised my concerns regarding this device and its potential for injuring patients. Nevertheless, in the current regulatory environment, I believe that it would be possible that the device could be approved for use by the FDA because of the lack of a clear standard from the FDA that the company prove empirical data regarding that the device is usable and safe.

The Department of Defense has been particularly forceful with contractors regarding insuring that members of the target population will be able to use systems within the environment of their intended use. It does not take a great deal of contemplation to understand the value of insuring that a system can be operated effectively by a soldier in a combat environment. A system that could save the lives of fellow soldiers or civilians would be useless if it could not be used effectively by a member of the target population (i. e., a soldier) in combat. If the user interface is too cumbersome or complicated when used in the stress and difficulties of the combat environment, then all the time and effort taken to create that system has been wasted. NASA and the FAA have taken a stance similar to the DoD. The Department of Transportation in conjunction with Congress have taken a strong stance with respect to the design of user interface of vehicles.

I believe that the FDA will begin to strong stance similar to other regulatory bodies of the Federal Government regarding insuring that the user interfaces of medical devices meet specific usability standards and the meeting of these standards must be demonstrated experimentally with empirical data. I think that one of the first step in the process of ever increasing regulation of the user interfaces of medical will be the adoption of HE75 by the FDA. This would start the process towards mandating that companies prove their products meet user performance standards.


  1. One option for evaluating user interfaces is utilizing computer-based simulated prototypes to test and design iteratively throughout the medical device development process.

    Red4 Simulations builds custom simulations that record user responses, thus providing empirical data that can be used to justify a device's usability.

    I look forward to your discussion of the new HE 75 standard.

  2. Tammie. My read of HE75 suggests that you are absolutely on the mark regarding iterative testing and the need for it throughout the product development process. I shall be interested to see how the FDA enforces the iterative usability testing requirement of HE75.

    I'm always interested in tools that support usability work. I'll investigate Red4 Simulations and if I decide to write an article about it, I'll write the article with respect to how the tool would support the fulfillment of HE75.