Product assessment example
Here we will discuss a very straightforward approach to product assessment: expert assessment based on identifying the product capability demands and mapping those demands on to the DFS scales and underlying population data to calculate the level of exclusion.
An example of the simple assessment form used for an acoustic guide device for use in museums and art galleries can be seen by clicking on the image to the left. Scores are given according to the descriptions of the scale items. If there is no obvious link between the description and the user-product interaction, subjective analogy is used to infer the most appropriate score.
For example, there is no relevant description in the DFS scales of the dexterity capability required for pressing buttons on the device. Comparison is thus made based on existing descriptions. It is assumed that the required capability of squeezing water from a sponge (score 8.0) is comparable to pressing buttons, as both actions are related to the exertion of finger strength. Therefore a score is made with this reference (see the table row for dexterity in the example).
A rough estimation of numbers of people excluded is thus available by mapping the scale to the GB population. In this case, the compiled exclusion resulting from each capability demand is as shown in the table below. However the total exclusion will not be the sum of the seven component numbers of people excluded on the grounds of individual capabilities as shown in table, because of multiple counting.
| Disability | Score | Exclusion |
|---|---|---|
| Locomotion | 7.5 | 1 031 000 |
| Reach & stretch | 8.0 | 116 000 |
| Dexterity | 8.0 | 423 000 |
| Vision | 4.5 | 387 000 |
| Hearing | 5.5 | 400 000 |
| Communication | 5.5 | 74 000 |
| Intellectual functioning | 9.5 | 115 000 |
The following two sections describe in more detail how such assessment may be applied to a range of domestic products and give examples of quantified design exclusion.