Ezrielev et al.
| Category | Heard | PPB | Easy % | Medium % | Hard % |
|---|---|---|---|---|---|
| Mythology | 17 | 16.47 | 94% | 59% | 12% |
| Philosophy (19th/20th Century) | 4 | 15.00 | 100% | 50% | 0% |
| Philosophy (Ancient/Medieval) | 3 | 16.67 | 100% | 67% | 0% |
| Philosophy (Any/Other) | 1 | 10.00 | 100% | 0% | 0% |
| Philosophy (Contemporary) | 4 | 20.00 | 100% | 100% | 0% |
| Philosophy (Early Modern) | 4 | 12.50 | 75% | 25% | 25% |
| Religion (Any/Other) | 5 | 12.00 | 80% | 40% | 0% |
| Religion (Buddhism) | 5 | 18.00 | 100% | 60% | 20% |
| Religion (Christianity) | 8 | 12.50 | 100% | 13% | 13% |
| Religion (Hinduism) | 2 | 10.00 | 100% | 0% | 0% |
| Religion (Islam) | 4 | 12.50 | 100% | 25% | 0% |
| Religion (Judaism) | 4 | 15.00 | 75% | 75% | 0% |
| Religion (Other Subcontinent) | 1 | 10.00 | 100% | 0% | 0% |