Hierarchical task analysis versus cognitive work analysis: comparison of theory, methodology, and contribution to system design

The cognitive work analysis framework continues to attract increasing attention
from the human factors and ergonomics community. Conversely, hierarchical
task analysis has been, and remains, the most popular of all human factors and
ergonomics methods. This article compares the two approaches in terms of their
theoretical underpinning, methodological approach and potential contributions
to system design and evaluation. To do this, recent analyses, involving both
approaches, of a military rotary wing mission planning software tool are
compared and contrasted in terms of their methodological procedure and analysis
outputs. The findings indicate that, despite the very different theoretical and
methodological nature of the two approaches, and also the entirely different
analyses derived, the two methods provide highly complementary outputs. In
conclusion, it is argued that there is benefit in applying both approaches to inform
the design and/or evaluation of the same product or system.