| Index | Duncan | Oklahoma | National |
| Average Test Scores | 32% | 32% | 48% |
| Student/Teacher ratio | 22:1 | 22:1 | 16:1 |
| Total public schools | 12 | 1,346 | 79,221 |
| Total private schools | n/a | 159 | 24,874 |
| Total post-secondary schools | 1 | 178 | 7,963 |
| Index | Duncan | Oklahoma | National |
| Completed 8th grade | 80.9% | 83.5% | 84.3% |
| Completed high school | 79.4% | 82.2% | 83.0% |
| Completed some college | 48.7% | 55.6% | 59.4% |
| Completed associate degree | 24.5% | 31.9% | 38.5% |
| Completed bachelors | 19.6% | 24.5% | 30.3% |
| Completed masters | 5.8% | 8.1% | 11.5% |
| Completed professional degree | 2.2% | 2.3% | 3.3% |
| Completed doctorate | 0.9% | 1.0% | 1.3% |
There are a total of 12 public schools, n/a private schools and 1 post-secondary schools in Duncan. Using the proficiency score averages, the average test scores for Duncan, OK schools is 32%. The average student to teacher ratio is 22:1. In Duncan, OK, an average of 80.9% of students have completed 8th grade and an average of 79.4% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Marlow, OK | 4,455 | 32% | 32.8% |
| Comanche, OK | 1,896 | 30% | 38.3% |
| Duncan, OK | 22,529 | 32% | 32.9% |
| City | Population | Avg. Test Scores | National Avg. |
| South Lake Tahoe, CA | 22,535 | 37% | 22.6% |
| Hopewell, VA | 22,500 | 72% | 50.4% |
| Greenfield, IN | 22,561 | 62% | 29.9% |
| Dolton, IL | 22,487 | 10% | 79.3% |
| Mandan, ND | 22,482 | 45% | 7.3% |
| Duncan, OK | 22,529 | 32% | 32.9% |
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