• User Need vs Specification | Why It Matters Series

  • User Need vs Specification: What’s the Difference?

    A client reached out about a new device and had a very specific request: “I need the device to be three centimeters long.”  There are two ways to address this.  One way is to make a three-centimeter-long device.  The other is to is to understand why the request is for a particular length.

    What Are User Needs?

    What the client gave was a specification. Ideally, what the client should provide is a user need.

    User needs are what the user (or inventor) wants the device to do.  User needs help determine the functional, performance, environmental, usability, and safety requirements of a device. They can be quantitative, but they typically are not.

    Imagine a world where keyboards, computers, and monitors had been invented, but no document writing programs; no word processors, slide decks, or emails. A client has this great idea to invent keyboard to on-screen text. They approach you, the developer, and say, “When I type a key that letter should appear on the monitor 4mm tall.”

    The height of 4mm may make a lot of sense to the inventor right now, but what about some other person in the future? What if some other person wants to position the monitor closer or further away than the inventor sets theirs.  What if someone later creates a device that puts the monitor twenty feet away on a ten-foot-wide screen?  Does 4mm still make sense?  What if the monitor is built into someone’s contact lenses?

    In this case, we should ask the inventor a series of questions to challenge the assumptions and get at the underlying user need.  We may find that the user need is really, ‘must be legible during normal use.’  This gives the designer the flexibility to develop specifications that satisfy the user needs.

    What Are Specifications?

    Specifications are the design solution to the user need.  They should be defined in such a way that they can be verified by objective, quantifiable means during design verification.  Typically, this means that they are quantitative and measurable.

    In our scenario above 4mm may be the ideal specification for the height of a character. More likely, it will be a ratio proportion to the screen size such as ‘diagonal monitor size to character height ratio of 90:1.’

    Challenging Assumptions to Create an Excellent Device

    Making incorrect assumptions can cause consequences that may not be detected until late in the development process or once the product is on the market.  The lost time, lost revenue and additional cost can be significant.  When a user need is described in the form of a specification take the time to ask more questions.  Respectfully challenge the inventor about the possibilities of other users using the device in different environments now and in the future.  This approach will help develop an effective device that could serve more users in broader situations for a longer period of time.

    Seeking Strategic Guidance

    Are you in the beginning stages of design and development and looking for an experienced partner to help bridge the gaps from concept to commercialization with strategic guidance? MedTech Launch, a leading source for excellence in medical device design and engineering services, can help. Contact us today to discuss your innovative project.