Estimation of Operator Input and Output Workload in Complex Human-Machine-Systems for Usability Issues with iFlow.

Usability studies often use methods focused on product parameters. Test designs are processed in laboratories and evaluation is commonly performed by expert opinions. For validation studies we want to point out the importance of field studies and user and system oriented evaluation. For this purpose we want to present the methodological approach iFlow information flow as multiple assessment technique for usability issues in real or quasi-real simulated situations. The idea of iFlow is to assess input and output workload via video and audio recordings combined with subjective and objective measurement techniques of workload. In this contribution the iFlow method and an evaluative study in anesthesiology are presented. The added value to already existing methods and approaches is considered in the sensitivity of iFlow to identify situations of overload in a descriptive way. For design interventions it would be helpful to consult the iFlow chart to deduct cause and effect relations.