Proper allocation of tasks between humans and machines is an important component of user centred design. First identify which tasks can only be allocated to either the machine or human (mandatory allocation), and then provisionally allocate tasks on either a permanent and dynamic basis. This provisional allocation should then be evaluated and revised if necessary.
Tasks should be allocated to humans and machines in a way that best combines human skills with automation to achieve task goals, while supporting human needs.
Context analysis and task analysis should be used to identify the task structure and demands, the knowledge needed to perform the tasks, environmental constraints, functional and safety requirements, and any other relevant issues.
Mandatory allocation can be identified from the task model, e.g.
- to humans due to technical infeasibility or ethical or safety considerations
- to machines due to demands exceeding human capabilities or a hostile environment
Permanently allocate tasks based on factors such as task criticality, cost, training or knowledge requirements, or task unpredictability.
Dynamically allocate tasks based on factors such as human workload, the need for cognitive support, individual differences in users, changing capacity of the user, or organisational learning.
Jobs must be designed from the tasks based on factors such as responsibility, task variety, interference between and within tasks, communication between users, and individual capability.
The provisional allocations and jobs should be evaluated based on factors such as: safety, system performance, usability, cost, job satisfaction and human well-being, acceptance by users, management and society and social impact. The evaluation findings should be used to review and revise the provisional allocations which should then be re-evaluated.
This procedure is based on:
Allocating Tasks between Humans and Machines in Complex Systems Mark-Alexander Sujan and Alberto Pasquini, 4th International Conference on Achieving Quality in Software, Venezia, 1998
Older, M.T., Waterson, P.E. and Clegg C.,W. (1997) A critical assessment of task allocation methods and their applicability. Ergonomics, 40(2): 151-171.
Ip, W.K., Damodaran, L., Olphert, C.W. & Maguire, M.C. (1990). The use of task allocation charts in system design - a critical appraisal. In D. Diaper, G. Cockton, D. Gilmore & B. Shackel, Eds. Human-Computer Interaction INTERACT'90, pp. 289-294. Amsterdam: North-Holland.©UsabilityNet 2006. Reproduction permitted provided the source is acknowledged.