Validation of Device Concept
A suggestion for a new device or an improvement to an existing one may come from a small number of users, or even an individual. Care should be taken when generalising the findings from small numbers of individuals as their perceptions, needs and attitudes may not be representative of the whole user group. For this reason, initial ideas about a device should be validated by further research with a larger and more representative group of potential users before device design begins. An idea for a new medical device may also result from the development of a new technology. Such an idea will also have to be validated and refined with users to ensure that the new technology is developed into the most appropriate device.
If stage 1 can be seen as asking ‘is there a need for this device?’ then stage should answer the questions: ‘is there really a need for this device, and if so, then what is the specific need?’
User involvement at this stage is critical to ensure that the device produced is the right device: a device that will meet an un-met, or poorly-met, need. Producing a device that is clinically effective and safe is not sufficient. A well conceived and well designed device will help healthcare professionals carry out their work effectively and efficiently and improve health outcomes; a better quality of life; to become (or remain) more independent and to retain their dignity: such a device can truly be deemed to meet the requirements of its users.
The aims of the user requirements research at this stage in development are to gather information on:
- The clinical pathways and the healthcare system that the device will be part of. This will be required to identify the situations that will constitute ‘normal use’. It will also be required to identify the potential safety issues and risks that may arise either from ‘normal use’ or ‘use errors’.
- The working patterns of the potential users. This will be required to identify the factors that may prevent uptake of the device; such factors may include the need for a device to be a particular size or weight, to be portable, to be compatible with certain other devices or to include certain accessories. Also, what constitutes normal use and the risks associated with this are important issues when seeking regulatory approval for a medical device.
- The attributes of the potential users. This will allow decisions to be made on the training requirements for the device. When considering who the users are this should include not only the ‘target users’ who the device is actively designed for but also any other individuals who may also happen to use the device.
- User opinions on device design. As well as providing opinions on designs that developers have suggested, users may also come up with innovative and useful ideas on device design and should be encouraged to do so.
What constitutes normal use and the possible risks that may result from this are important issues for regulatory approval. This information will allow you to identify issues that may affect the uptake of the device such as the training requirements of the potential users, the other devices that it will be required to work alongside as well as any potential impact on the safety of patients or the health and safety of users. Performing and documenting these processes in the usability engineering file is required by the standard IEC 60601-1-6. Devices that have a user interface may require additional research at this stage to elicit specific information on this aspect of design.
Research at this stage will allow developers to identify the factors that will contribute to make a successful device. Once the critical issues have been identified this will allow the developers to decide on the measures to use during the evaluation stage.
Examples of these criteria include:
- Programming the device must take no more than 90 seconds.
- The device will need to be easy to learn to use for a wide range of users including those with no professional training.
- The device must be compatible with devices x and y.
- The device must be usable by people with severe arthritis.
There are a number of research methods that can be employed at this point in development (figure 1). One factor that will affect the choice of method is whether you are interested in capturing the views of individuals or the views of a group.
The interaction that results from a group can result in a large number of opinions and experiences as participants bounce ideas off each other, although in these situations an individual may find it difficult to express an opinion that conflicts with the rest of the group. Studying individuals may be more appropriate in circumstances where a delicate or personal topic is being discussed or when there are practical problems with getting a group of users together at the same time. Methods such as focus groups and Delphi technique are useful in obtaining a consensus opinion from a group, whereas techniques such as interviews and questionnaires can gather opinions of individuals.
The outcomes of research at this stage in development should be the information necessary to develop one or more prototype design including identifying the factors that may prove a barrier to the uptake of the device. Developers will be able to draw conclusions such as the device will need to be no bigger than x; no heavier than y and will need to be compatible with devices a, b and c.
At this point, some difficult design decisions may have to be made. For many devices the potential users will be a wide variety of people, potentially including both professional and lay users and with differing specialities, skills and abilities. Even within user groups that appear to be more homogenous individuals will have differing work patterns and habits, not to mention attitudes, opinions and preferences. Once the requirements of all users have been identified therefore, conflicts will have to be resolved. This will require decisions to be made on who the target users should be: those users who needs should be prioritised during design. However, designers must also be mindful of the other clinical and non-clinical users who will also use the device.
Research performed at this stage can also contribute to the development of a health economic or business model and to market research. Outcomes should include:
- Who will the target users be?
- Who will make the decision on whether to purchase the device?
- What is expected benefit of the device (in terms of improved efficiency, safety and patient outcomes)
Methods that are particularly useful for validating and refining the concept for a new device include:
- Focus groups
- Delphi Technique