MAP-01-011 HFI Technical Guide - Human Factors Integration ...

Annex 3 – HF Techniques, Methods and ToolsOperability criteria links mission-critical user performance to the specifics of thedesign, for example a user performance criterion established for time to respondto a type of threat will be linked to the way that information about new threats isdisplayed. An alert about a new threat might be signalled to the user visually bya change to the display.Operability criteria will state parameters to which such an alert must conform, e.g.it must be possible to isolate the alert within x seconds, the user response mustbe achievable within y seconds etc. The way that the alert is designed on thedisplay (using shape, colour, brightness, position etc.) can then be designed tomeet, and be evaluated against, the stated criteria.General operability principles have been defined that apply to the overall designof user-equipment interfaces. For example, visual displays should be formattedin a way that is compatible with the actions to be performed by users. Thesegeneral principles are turned into specific operability criteria relevant to the classof equipment, the type of users and the tasks they must perform. Operabilitycriteria are therefore important in terms of trials planning and planning forAcceptance.Operability criteria are defined from Assessment phase onwards so that they areavailable for the evaluation of design options including commercial off-the-shelfcomponents. Criteria should be finalised early in Manufacture. HFI specialistscan advise on the form of such criteria for each class of equipment.The definition of operability criteria is essential for mission- and safety criticalaspects of the equipment. Costs and risks of development are reduced whenoperability criteria are defined prior to equipment design.• Advantages• The definition of operability criteria is essential for mission- and safetycritical aspects of the equipment.• Costs and risks of development are reduced when operability criteria aredefined prior to equipment design.• Disadvantages• Operability Criteria Definition can be time consuming and resourceintensive.A3.3.9User Performance CriteriaThe goal of User Performance Criteria is to develop quantitative and qualitativeexpressions of the human performance that must be achievable within the wholesystem. These are used to identify design requirements, to conduct designassessments and to perform trade-offs between system options.Human performance criteria are developed by decomposition of the overallsystem performance requirements. The allocation of functions will determine theoverall scope of human activity in the system and outline broad types ofMay 2006 Page A3-25 Issue 4