Table 3.
Corrected item-total correlation and Cronbach’s alpha for SMS subscores and total score for 6 sample medical raters.
| SMS item | Corrected item-total correlation | Cronbach’s alpha coefficient | |||||
|---|---|---|---|---|---|---|---|
| Rater 1 | Rater 2 | Rater 3 | Rater 4 | Rater 5 | Rater 6 | ||
| Total score | .951 | .943 | .962 | .938 | .961 | .948 | .983 |
| Trunk posture | .750 | .787 | .806 | .706 | .834 | .767 | .919 |
| Leg movement | .797 | .930 | .898 | .889 | .890 | .873 | .962 |
| Arm movement | .702 | .831 | .872 | .802 | .849 | .861 | .931 |
| Gait speed | .888 | .893 | .878 | .737 | .883 | .830 | .949 |
| Gait fluency | .815 | .848 | .801 | .772 | .839 | .847 | .939 |
| Stability/risk of falling | .900 | .903 | .920 | .911 | .922 | .932 | .974 |
| 0.8 | ≤ Corrected item-total correlation ≤ | 1 | High |
| 0.6 | ≤ Corrected item-total correlation < | 0.8 | Good |
| 0.4 | ≤ Corrected item-total correlation < | 0.6 | Moderate |
| 0.2 | ≤ Corrected item-total correlation < | 0.4 | Weak |
| Corrected item-total correlation < | 0.2 | Poor |
| 0.9 | < Cronbach’s alpha ≤ | 1 | Excellent |
| 0.8 | < Cronbach’s alpha ≤ | 0.9 | High |
| 0.7 | < Cronbach’s alpha ≤ | 0.8 | Acceptable |
| 0.6 | < Cronbach’s alpha ≤ | 0.7 | Disputable |
| 0.5 | < Cronbach’s alpha ≤ | 0.6 | Low |
| Cronbach’s alpha ≤ | 0.5 | Unacceptable |