The “designer friendly” Usability Specification

Getting your head around ISO 62366:2008 can, at the least, be tricky, perhaps even frustrating. The standard mentions many documents and requirements for a medical device Human Factors programme.

Take the Usability Specification as an example. It’s meant to provide testable requirements for usability verification and for usability of the primary operating functions. On top of these, it is also expected to include criteria for determining the adequacy of risk controls that have achieved by the usability engineering process.

With me so far?

Once you’ve deciphered these requirements for your Usability Specification, you’re next asked to;

  • add in inputs from a range of other documents (Application Specification, The Primary Operating Functions, Hazards and Hazardous Situations relating to Usability),
  • Include any foreseeable use errors associated with the medical device.
  • describe;
    • use scenarios related to primary operating functions, including frequent use scenarios,
    • reasonably foreseeable worst case use scenarios,
    • the user interface requirements for the primary operating functions and
    • whether the functions are easily recognisable by the user.

This is all great stuff providing you have generated all of this background documentation.

But, faced with the daunting prospect of documenting this mass of requirements probably go a long way towards explaining why project teams don’t often have a Usability Specification readily available when designing usability studies.

Many Medical Device Developers, us included, have struggled to generate Usability Specifications, often resorting to creating usability goals that often have meaningless acceptance criteria (e.g. 85% of users will be able to press the ON/OFF button).

Hope is on the horizon…

Appropriately for a human factors standard, ISO62366 is being redesigned to enable the users (medical device developers and manufacturers) to readily understand the requirements with which they must comply.

The most recent draft (2014) goes a long way towards potentially simplifying the specification requirements, as the Usability Specification looks to be experiencing quite a drastic overhaul. The intention is to split the document into a) the design features of the User Interface, removing duplication of the Use Specification and b) tie the Use Scenarios into the Risk Controls and categorise the scenarios and mitigations.

We’ve recently worked with selected clients to develop Usability Specification and Application Specification documents that provide a bridge between the currently complex (perhaps confusing) requirements and simplified expectations that are being embodied in late drafts of the revised standard.

The result? The project teams have documents that they can really understand, that aren’t lengthy and repetitive, and very importantly are supremely usable during design development and verification! We’ve learned lots along the way too.

Get in touch now to find out how you can benefit from the fruits of our recent learning, for your usability activities.

One thought on “The “designer friendly” Usability Specification

  1. Pingback: Web design: Getting to grips with your user’s experience | Ruth Stalker-Firth

Comments are closed.