| Score |
Description |
| -1 |
Clear empirical findings against the hypothesis. |
| 0 |
No empirical support (for or against the hypothesis). |
| 1 |
Anecdotal support only for the hypothesis. |
| 2 |
Multiple qualitative and/or quantitative studies with mixed results (i.e. some in favor, some against the hypothesis), but more negative than positive findings. |
| 3 |
Multiple qualitative and/or quantitative studies with mixed results (i.e. some in favor, some against the hypothesis), but more positive than negative findings. |
| 4 |
Single systematic case study supporting the hypothesis. |
| 5 |
Multiple case studies supporting the hypothesis. |
| 6 |
Comparative case study(ies) supporting the hypothesis. |
| 7 |
Single, high-quality quantitative analysis supporting the hypothesis. |
| 8 |
Multiple quantitative analyses supporting the hypothesis. |
| 9 |
Multiple empirical analyses, including at least one qualitative and one quantitative study supporting the hypothesis. |