Grading system for animal studies
| Strong | Model can be extrapolated to humans and the study is randomized, blinded, and placebo-controlled. Drug dosage is similar to clinical practice. |
| Average | The model does not match human disease, but is randomized, blinded, and placebo-controlled. The dosage of the drug is comparable with clinical practice. |
| Weak | Model cannot be extrapolated to humans. The study is not randomized, blinded, and placebo-controlled. |