Cronbach’s alpha | Internal consistency |
α ≥ 0.9 | Excellent (high-stakes testing) |
0.7≤ α < 0.9 | Good (low stakes testing) |
0.6 ≤ α < 0.7 | Acceptable |
0.5 ≤ α < 0.6 | Poor |
α < 0.5 | Unacceptable |