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 |