| Index | Duncan | Iowa | National |
| Average Test Scores | n/a | 69% | 48% |
| Student/Teacher ratio | n/a | 13:1 | 16:1 |
| Total public schools | n/a | 1,101 | 79,221 |
| Total private schools | n/a | 208 | 24,874 |
| Total post-secondary schools | n/a | 96 | 7,963 |

| Index | Duncan | Iowa | National |
| Completed 8th grade | 65.6% | 89.2% | 84.3% |
| Completed high school | 65.6% | 87.7% | 83.0% |
| Completed some college | 35.4% | 59.8% | 59.4% |
| Completed associate degree | 35.4% | 38.4% | 38.5% |
| Completed bachelors | 20.8% | 27.2% | 30.3% |
| Completed masters | 0.0% | 8.7% | 11.5% |
| Completed professional degree | 0.0% | 2.7% | 3.3% |
| Completed doctorate | 0.0% | 1.1% | 1.3% |
There are a total of n/a public schools, n/a private schools and n/a post-secondary schools in Duncan. Using the proficiency score averages, the average test scores for Duncan, IA schools is n/a. The average student to teacher ratio is n/a. In Duncan, IA, an average of 65.6% of students have completed 8th grade and an average of 65.6% have completed high school.
| City | Population | Avg. Test Scores | National Avg. |
| Kanawha, IA | 983 | 80% | 65.6% |
| Garner, IA | 3,134 | 78% | 63.0% |
| Forest City, IA | 4,267 | 75% | 55.9% |
| Ventura, IA | 783 | 74% | 54.2% |
| Britt, IA | 1,810 | 74% | 53.1% |
| Duncan, IA | 104 | n/a |
| City | Population | Avg. Test Scores | National Avg. |
| Whale Pass, AK | 104 | 50% | 4.2% |
| Dora, NM | 104 | 40% | 17.7% |
| Melstone, MT | 104 | 47% | 2.8% |
| Glenfield, ND | 105 | 30% | 37.5% |
| Weskan, KS | 105 | 45% | 6.3% |
| Duncan, IA | 104 | n/a |