1.10 Evaluations

　

A design may be developed by using anthropometric data from tables, with the necessary corrections, and sometimes a very satisfactory result can be obtained. However, dimensions interact in real situations so some form of dynamic test of a design is highly desirable. There are software packages available that will permit some degree of dynamic testing or simulation, including, for example, exploring the field of view, testing maintenance procedures or interactions between users. Users with a variety of anthropometric characteristics can be tested by using different percentile values in a simulation. Computer simulation or physical mockups should be used to test designs in order to examine the complex interactions between dimensions that occur in the use of equipment and performance of tasks. As far as possible the people used in tests with mockups should include some with body dimensions that represent the extremes used as design limits in arriving at the design being tested. In practice this is not always possible, so computer simulation models are a very attractive option and will become increasingly sophisticated and popular. It must be remembered though, that computer models are still limited by the lack of availability of anthropometric data for many populations of users. Tests using a mockup are called ‘fitting trials’ and the general idea is to provide adjustment to the important dimensions of the design mockup so that a sample of users can try out each dimension at different settings and say whether it is just right or too high/large or too low/small. The ‘method of limits’ is a convenient and systematic way to perform fitting trials. The setting is started in a position that is far too high/large (or far too low/small) and then adjusted in small steps until the person thinks that it is ‘acceptable’, then ‘just right’ and then ‘too low/small’ (high/large). This process may be repeated making adjustments from too small to too large (or vice versa) and then from too large to too small as many times as circumstances dictate and for as large a sample as practical. In this way a good idea of the range of settings that are acceptable to the population can be obtained. Fitting trials are especially useful for populations for which there may not be much detailed data available, like pregnant women, the elderly, or children. Both structural (static) and functional (dynamic) anthropometric data have applications in the design of facilities and things people use. The data to be used should be reasonably representative of the population that would use the item. When items are designed for specific groups, the data should be specific for such groups in the country and culture in question.

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