As a result of Poock's influential work in the early 1980s , command and control is generally believed to be one specific application where speech input holds great advantages over keyed data entry . However , a recent paper (Damper & Wood , 1995 ''Speech versus keying in command and control applications'' , International Journal of Human -Computer Studies , 42 , 289 -305) has questioned this interpretation of Poock's data because the experimental conditions seemed to bias the results against keyed entry . While Damper and Wood modelled their experiments on Poock's , however , there were important dif ferences which mean that their conclusions are uncertain . The objective of the work reported here was to determine if the major dif ference-the omission of concurrent , secondary tasking from their study-could explain Damper and Wood's observed superiority of keying over speech .
Simulated command and control experiments are described in which speech input , abbreviated command keying and full command keying are compared under dual-task conditions . We find that speech input is no faster (a nonsignificant 1 . 23% dif ference) and enormously more error-prone (1038% , highly significant) than abbreviated keying for the primary data entry task , but allows somewhat more (11 . 32% , not significant) of a secondary information -transcription task to be completed . Full keying has no advantages whatsoever : we believe that this confirms the methodological flaw in Poock's work . If recognizer errors (as opposed to speaker errors) are discounted , however , speech shows a clear superiority over keying . This
indicates that speech input has potential for the future-especially for high workload situations involving concurrent tasks-if the technology can be developed to the point where most errors are attributable to the speaker rather than to the recognizer .