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

Annex 3 – HF Techniques, Methods and Tools• Disadvantages• MCH is dated and uni-dimensional.• It was originally developed to rate controllability of aircraft.• Limited to manual control tasks.• NASA TLX and SWAT are more appropriate.• Data is collected post-trial. This is subject to a number of problems, suchas a correlation with performance. Participants are also poor at reportingpast mental events.A3.6.11Individual Self-Assessment (ISA)ISA is a very simple subjective workload assessment technique that wasdeveloped to assess air traffic controller’s mental workload during the design offuture air traffic management systems. It is based upon participants self-ratingtheir workload during a task (normally every two minutes) on a scale of 1 (low) to5 (high). Kirwan et al (DTC116 - 1997) used the following ISA scale to assess airtraffic controllers (ATC) workload.Typically, the ISA scale is presented to the participants in the form of a colourcodedkeypad, which flashes when a workload rating is required, and theparticipant simply pushes the button that corresponds to their perceived workloadrating. However, where appropriate, the workload ratings can be requested andacquired verbally.ISA allows a profile of operator workload throughout the task to be constructedand allows the analyst to ascertain excessively high or low workload parts of thetask under analysis. The main appeal of the ISA technique lies in its lowresource usage and its low intrusiveness.• Advantages• ISA is a very simple technique to learn and use.• The output allows a workload profile for the task under analysis to beconstructed.• ISA is very quick in its application as data collection occurs during the trial.• Has been used extensively in numerous domains.• Requires very little in the way of resources.• Whilst the technique is obtrusive to the primary task, it is probably the leastintrusive of the on-line workload assessment techniques.• Low cost.May 2006 Page A3-53 Issue 4