| Experimental ergonomic evaluation with user trials: EEE product development procedures | ||
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The exact measures described in 5.1 could be checked subjectively in terms of the body and the senses and opinions. While EEE1 is more oriented to physical ergonomics, EEE2 is amenable to both physical and psychological or cognitive ergonomic evaluations.
There were no differences between the expert’s and the subjects’ scores of heights (paper II). However, there was a statistically significant difference between the ratings of different heights. The inter-rater consistency showed the ratings to be as expected; the 7-point scale was functional in a logical and realistic way. The intra-rater consistency revealed no statistically significant differences between the ratings, and the simulator evaluation can hence be considered reliable.
The methods applied to the rating and the expert evaluation proved to be useful and practicable for studying task-surface heights (paper II). The main conclusion was that the height evaluations based on the subjects’ rating were supported by the expert’s evaluations, the exact anthropometric data, their comparisons and also by the literature as far as reliability and even validity are concerned. Since some of the subjective assessments appeared to be illogical, it can be recommended that assessments should not be used alone, because so many other variables apart from height can obviously affect the assessments.
In the study on the videoconferencing system (paper VII), the statements that correlated statistically significantly were shown collectively in Table 4 in paper VII.
The EEE2 procedure can be described as follows:
Experts collect data on a product (paper II) or a system (paper VII) and its users.
Experts as a team formulate the characteristics (paper II) or statements (paper VII) for the rating and the scale to be used.
Communication with end-users should be emphasised.
End-users rate the characteristics or statements.
An expert observes the subject’s performance on video and makes relevant ratings.
The scores are processed statistically.
The products, their features, the user groups’ opinions and expert evaluation can be compared. The agreement can be statistically analysed.