Comparison (Paired t-test) of Note Types for Perceived Workload (NASA-TLX) and Usability (SUS)
| Note | Note | Paired t-Test Results | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| A | B | C | D | A Versus B | A Versus C | A Versus D | |||||
| Mean | SD | Mean | SD | Mean | SD | Mean | SD | P-Value | P-Value | P-Value | |
| TLX—Mental | 3.25 | (1.69) | 3.00 | (1.32) | 2.50 | (1.83) | 2.56 | (1.36) | .52 | .21 | .21 |
| TLX—Physical | 1.75 | (1.13) | 1.56 | (0.81) | 1.44 | (0.73) | 1.38 | (0.72) | .38 | .33 | .23 |
| TLX—Timing | 4.25 | (1.57) | 4.31 | (1.49) | 3.25 | (1.95) | 3.50 | (1.71) | .85 | .12 | .18 |
| TLX—Performance | 3.81 | (1.47) | 3.63 | (1.45) | 2.69 | (1.70) | 3.31 | (1.54) | .66 | .048 | .43 |
| TLX—Effort | 3.94 | (1.77) | 3.50 | (1.32) | 2.88 | (2.00) | 2.69 | (1.74) | .30 | .13 | .043 |
| TLX—Frustration | 3.31 | (1.78) | 2.69 | (1.54) | 2.75 | (1.98) | 2.63 | (1.75) | .01 | .41 | .28 |
| TLX—Overall | 3.39 | (1.21) | 3.11 | (0.86) | 2.58 | (1.51) | 2.68 | (1.14) | .24 | .11 | .10 |
| SUS* | 58.50 | (22.22) | 74.83 | (15.10) | 81.83 | (21.9) | 77.50 | (26.86) | .007 | .005 | .009 |
↵* There was one subject who had missing data for note A. This subject was excluded from analysis specific to SUS. Bold reflects significant mean differences where P < .05.
Note models: A (traditional SOAP), B (two-column APSO), C (collapsible APSO), D (two-column collapsible APSO).
NASA-TLX contains 6 subscale items and an overall mean subscale score, each on a 7-point Likert scale in which lower TLX scores indicate less workload.
System Usability Scale (SUS) is reported as a raw score (scale of 0 to 100) in which larger values are considered better usability.
TLX, Task Load Index; APSO, assessment, plan, subjective, objective; SOAP, subjective, objective, assessment, plan.