The Low-Event Task Subjective Situation Awareness (LETSSA) technique: Development and evaluation of a new subjective measure of situation awareness

Situation awareness (SA) is an important component of an individual's ability to function in a complex environment. As such, it is essential to have effective measures of an individual's SA. The most widely used subjective measure of SA is the Situation Awareness Rating Technique [SART]. However, SART has been criticised for not predicting performance or objective SA, and being highly correlated with workload. This paper describes the development and testing of a new subjective measure of SA, the Low-Event Task Subjective Situation Awareness (LETSSA) measure. To evaluate LETSSA a train simulator study was conducted with 23 novice and 26 expert freight train drivers. LETSSA was able to detect differences in manipulated SA and was comparable to an established objective SA measure (SAGAT). LETSSA was significantly associated with performance but not significantly associated with workload. While further validation is required, LETSSA shows promise as an effective subjective measure of SA.