W/INDEX: A Predictive Model of Operator Workload

Diagnosticity and multidimensional subjective workload ratings

“…The Workload Profile procedure has in common with another multidimensional procedure-Workload Index (W/INDEX, North and Reiley 1988), the assumption that workload dimensions can be defined by the resource dimensions hypothesized in the multiple resource model of Wickens (1987). The various workload dimensions represent the different demands that can be imposed by a task: perceptual/central processing, response selection and execution, spatial processing, verbal processing, visual processing, auditory processing, manual output, and speech output.…”

“…With W/INDEX, researchers knowledgeable about the tasks to be performed and familiar with the theoretical background of the resource dimensions (subject matter experts) would make a programmatic estimate a priori. The estimate is a workload index used to predict -the eventual performance, especially time-shared performance (North andReiley 1988, Sarno andWickens 1991). The Workload Profile procedure examines the diagnosticity afforded by the multidimensional ratings provided directly by the subjects who have actually experienced the tasks and who are not necessarily familiar with the theoretical framework or predictions.…”

The Operational Demand Evaluation Checklist (ODEC) of workload for railway signalling

“…The focus on theories of information processing is evident when reviewing the ''traditional'' human factor tools used to assess workload (Pickup and Wilson, 2002). These typically have been designed for use within simulators and generally do not appear practical for use in field based workload assessments or within a live system in real time (Beatty, 1982;Wierwille et al, 1985;North and Riley, 1989;Meshkati et al, 1990;Army Research Laboratory, 2002). It could be suggested that these types of workload assessments, familiar to human factor practitioners, have driven the interpretation of the concept itself.…”

Queueing Network-Model Human Processor (QN-MHP)

“…These models include the instrument monitoring and visual sampling models (e.g., Senders [1964]; Carbonell [1966]; Senders and Posner [1976]; Schmidt [1978]), one-server queueing models of Rouse and his colleagues [Rouse 1980;Chu and Rouse 1979;Walden and Rouse 1978;Greenstein and Rouse 1982], and engineering models of attention allocation and task selection [Sheridan 1972;Siegal and Wolf 1969;Kleinman and Curry 1977;Tulga and Sheridan 1980;Pattipati et al 1983]. Simulation models of human performance, such as, the MICROSAINT model [Laughery 1989;Laughery and Corker 1997], and the WINDEX model [North and Riley 1989], have started to accommodate some of the parallel processing assumptions of the multiple resources models. These models assume that the human has multiple pools of resources, which can be simultaneously allocated to multiple tasks in a graded fashion and allow parallel processing of simultaneous tasks as long as the needed resource(s) is(are) available (for example, Wickens [1984]; Wickens and Liu [1988]).…”