This page will consider the main models associated with AT design.

Ensuring the person-centredness of a system is critical. Many AT systems are designed without considering the individual who will be expected to use it. The ultimate expression of technology failure is when the technology is rejected by the person who should ideally be benefiting from it. Attempts to avoid rejection often focus on considering the disease or disability of a person rather than the person themselves. Just as people concentrate on DIS-ability rather than ABILITY. What people CAN do is critical to any good design specification. Similarly, what people ACTUALLY do, as opposed to reportedly do, is also critical. With this in mind, this page attempts to unpack many of the most common models associated with assistive technology.

Before I begin, a critical starting place is http://www.utoronto.ca/atrc/reference/atoutcomes/ATOTools.html which is a page at Toronto University and covers in greater detail much of the below.

These include those of Marcia Scherer's 'Matching Person to Technology' (MPT) in which the person is located in a series of structures that bind At design. The idea is the person has the technology selected, accommodates the the new technology, uses it and evaluates it and so on in an iterative cycle. Other factors that Scherer notes are highlighted in this diagram and include wider sociopolitical, socioeconomic and socio-cultural aspects

The central focus of Scherer's model is the user but what is important to acknowledge is her understanding that AT is a socio-cultural phenomena and does exist in a vacuum. Sociopolitical and economic forces define availability, acceptance and rejection of system as well as individuals. Scherer also considers certain aspects of human activity that other people side step as the diagram below demonstrates.

"The Matching Person and Technology (MPT) process is both a personal and collaborative (user and provider working together) assessment and consists of a series of paper-and-pencil measures that can also be used as interview guides. A range of assessments are offered from a quick screen, to specialized evaluations (which can be completed in approximately 15 minutes) to a comprehensive assessment (which can be completed in 45 minutes by someone trained and experienced in using the forms). The MPT process is applicable across a variety of users and settings. Of particular interest for this article is the form, "Assistive Technology Device Predisposition Assessment (ATD PA)... The development and validation of the ATD PA followed the recommended steps for test/measure construction as follows: (1) concept definition and clarification, (2) draft of items and response scales, (3) pilot testing, and (4) determination of measure quality and usefulness." (Sherer, M (2005) online)

Hence AT design is concerned with assessing the person and the technology and ensuring a 'fit' so that rejection is minimized. I wholly recommend having a read of some of Marcia Scherer's books (especially 'Living in the state of stuck') and checking out her web site. The following table might be a useful source of information on some of the key models:

A great place to start looking at AT model is to look at the article by Batavia AI, Hammer GS. (1990) "Toward the development of consumer based criteria for the evaluation of assistive devices". Batavia and Hammer are interesting as they developed a system for quantifying the elements of AT system. These elements have many similarities with the ones we have developed in our Domestic dependability Model. The main elements that the consider to be important are:

Many of the models are predominantly concerned with 'outcome measures'. These are often quantitative measurements that can be used to justify to policymakers the efficacy of an assistive technology. What is clear about the quantitative measures is they will often miss the point by measuring the wrong thing. We can measure if the technology works and if the person has appropriate alerts from the technology, but we cannot determine what the person is really feeling from these measures. Does the technological intervention cause adverse effects, is it debilitating the person in any way? is the technology causing a reduction in other important services which mean the person has less contact time with people?. People often reply that they use the technology when in reality they have it stuffed in a cupboard out of sight for a number of reasons. "Not wishing to appear stupid" is clearly a big one in the UK, just as "not wanting to look disabled", along with many others. For people to experience these reasons for rejecting technology the design must have failed and been undependable.