Carl Westin

5-6 Results 103 5-6-1 Acceptance The acceptance ratio of resolution advisories across conditions is shown in Figure 5- 5(a). Overall, 26 of 36 resolution advisories were accepted (72.2%). Conformal ad- visories were accepted more often (77.8%) than nonconformal advisories (66.7%). Acceptance did not vary as a result of interface transparency alone, with 72.2% of all advisories accepted in both conditions. The Cochran’s Q test indicated no effect between transparency and conformance conditions on the acceptance of advisories. A boxplot showing the agreement rating across conditions is shown in Figure 5- 5(b). Results indicate that the conformance effect was partly reversed under the TRI condition. While agreement decreased with conformance when using the HB, the opposite was found in the TRI condition, with the highest agreement found in the nonconformal condition. This suggests that the TRI interface improved participants’ understanding of nonconformal advisories, perhaps directing their attention to a solution they did not think of. Note that acceptance, however, was unaffected. A Friedman’s test showed no significant effects between conditions on participants’ agreement ratings of resolution advisories. 5-6-2 Performance and interface usage Response time was measured from advisory onset to time of acceptance or rejection, and varied between 4.1 and 21.8 seconds. The variation in response time across con- ditions is shown in Figure 5-6(a). Interface transparency appears to have influenced participants’ response time to advisories. Conformal advisories were responded to faster in the TRI condition, while nonconformal advisories were responded to faster in the HB condition. However, a Friedman test revealed no significant effects of transparency or conformance on response time. Figure 5-6(b) shows the boxplot for j o Accepted HB cfY HB cfN TRI cfY TRI cfN Rejected Acceptance [%] 0 20 40 60 80 100 (a) Acceptance o HB cfY HB cfN TRI cfY TRI cfN 0 Agreement rating [z-scored] 1.80 1.20 .60 -.60 -1.20 -1.80 (b) Agreement F IGURE 5-5: Bar chart with advisory acceptance ratio (a) and boxplot of agreement ratings (b) ( N = 9).