Table 3

System Usability Questionnaire score summary (N = 102)*

QuestionScore, mean ± SDResponse categories, n (%)
0 (strongly disagree)1234 (strongly agree)
1. I think that I would like to use this system frequently.3.7 ± 0.71 (<1)1 (<1)5 (5)16 (16)79 (77)
2. ►I found the system unnecessarily complex.3.6 ± 0.873 (72)18 (18)7 (7)4 (4)0 (0)
3. I thought the system was easy to use.3.6 ± 0.70 (0)0 (0)9 (9)26 (25)67 (66)
4. ►I think that I would need the support of a technical person to be able to use this system.3.7 ± 0.783 (81)14 (14)1 (<1)3 (3)1 (<1)
5. I found the various functions in this system were well integrated.3.4 ± 0.70 (0)1 (<1)10 (10)34 (33)57 (56)
6. ►I thought there was too much inconsistency in this system.3.5 ± 0.765 (64)26 (25)10 (10)1 (<1)0 (0)
7. I would imagine that most people would learn to use this system very quickly.3.3 ± 0.81 (<1)2 (2)12 (12)34 (33)53 (52)
8. ►I found the system very cumbersome to use.3.6 ± 0.772 (71)22 (22)5 (5)3 (3)0 (0)
9. I felt very confident using the system.3.7 ± 0.60 (0)1 (<1)2 (2)28 (27)71 (70)
10. ►I needed to learn a lot of things before I could get going with this system.3.4 ± 0.963 (62)29 (28)3 (3)4 (4)3 (3)
Composite score88.8 ± 10.4
  • *The System Usability Questionnaire is a 10-item questionnaire administered at the end of the study period in which the participant used the PLGS system to determine the system usability of the PLGS feature.

  • †Responses are ranked on a 5-point scale from 0 (strongly disagree) to 4 (strongly agree). For positively worded items (items 1, 3, 5, 7, and 9), each participant’s response is scored as recorded. Items denoted by “►” (items 2, 4, 6, 8, and 10) were reverse-scored by subtracting the response ranking from 4. Higher scores denote better perceived usability.

  • ‡Composite scores are calculated in accordance with the System Usability Questionnaire scoring manual by taking the sum of the individual item scores from each participant and multiplying by 2.5. Possible composite scores range from 0 to 100, with higher scores denoting better perceived usability.