Iowa’s nonpublic schools continue to show strong academic performance on the Iowa Statewide Assessment of Student Progress. A review of Iowa Department of Education proficiency data from the 2020-21 school year through the 2024-25 school year shows that nonpublic schools posted higher proficiency rates than public schools in every comparable subject and year.
The comparison includes English language arts, math, and science proficiency results by school and grade. English language arts and math data are available for all five school years, while science data begins in the 2021-22 school year in the public school files, so science trends cover a shorter period.
Nonpublic Schools Remain Ahead in Every Subject
In 2024-25, nonpublic schools had a clear proficiency advantage in each subject. Nonpublic students posted an 85.2 percent proficiency rate in English language arts, compared to 73.6 percent for public school students.
The same pattern appeared in math and science. Nonpublic schools posted an 81.7 percent proficiency rate in math, compared to 71.0 percent for public schools, and a 76.7 percent proficiency rate in science, compared to 67.2 percent for public schools.
These are not small differences. In 2024-25, the nonpublic advantage was 11.6 percentage points in English language arts, 10.7 points in math, and 9.5 points in science.
The Gap Has Narrowed, But It Has Not Disappeared
While nonpublic schools remained ahead, public schools improved more over the five-year period. In English language arts, the gap narrowed from 14.3 percentage points in 2020-21 to 11.6 points in 2024-25.
The narrowing was even more pronounced in math. Public school math proficiency increased from 65.0 percent in 2020-21 to 71.0 percent in 2024-25, while nonpublic math proficiency increased from 80.6 percent to 81.7 percent over the same period.
Science also showed a smaller gap by 2024-25. The nonpublic advantage in science narrowed from 14.5 percentage points in 2021-22 to 9.5 points in 2024-25.
Public Schools Showed a Recovery Pattern
The public school trend looks like a recovery story, especially in math. Public school math proficiency was essentially flat from 2020-21 to 2021-22, but then increased sharply in 2022-23 and continued to improve modestly through 2024-25.
Public school English language arts also improved over the full period. The statewide public school ELA rate increased from 68.7 percent in 2020-21 to 73.6 percent in 2024-25.
Science followed a somewhat different pattern. Public school science proficiency dipped in 2023-24, but rebounded strongly in 2024-25 to reach the highest level in the available science data.
Nonpublic Schools Started High and Stayed High
The nonpublic trend is different because the starting point was already much higher. Nonpublic proficiency rates were already above 80 percent in English language arts and math in 2020-21, leaving less room for large gains.
Even so, nonpublic schools improved modestly over the period. English language arts increased from 83.0 percent in 2020-21 to 85.2 percent in 2024-25, while math increased from 80.6 percent to 81.7 percent.
Science also improved from 74.5 percent in 2020-21 to 76.7 percent in 2024-25. However, nonpublic results generally peaked around 2022-23 before softening slightly in the following two years.
High School Math Is One of the Clearest Differences
One of the most notable findings is the difference in high school math. In 2024-25, public high school math proficiency was 66.6 percent, while nonpublic high school math proficiency was 81.7 percent.
That 15.1-point gap was the largest 2024-25 grade-band gap in the comparison. It suggests that math performance at the high school level deserves closer attention when comparing Iowa’s public and nonpublic sectors.
The smallest 2024-25 gap was in elementary math. Public elementary math proficiency was 73.9 percent, compared to 80.9 percent for nonpublic elementary schools.
School-Level Trends Show Broad Public Improvement
At the school level, public schools showed broader improvement from the first year to the final year in the data. Among public schools with enough tested students for a fair endpoint comparison, the median change was a gain of 5.8 percentage points in English language arts and 6.4 points in math.
Nonpublic schools also improved at the school level, but the median gains were smaller. Among comparable nonpublic schools, the median change was a gain of 2.8 percentage points in English language arts and 0.7 points in math.
That does not mean public schools outperformed nonpublic schools overall. It means public schools, starting from a lower baseline, showed larger gains during the period analyzed.
The Nonpublic Testing Universe Expanded Significantly
One major caution is that the nonpublic testing universe changed over time. The number of nonpublic schools with test data increased from 116 in 2020-21 to 169 in 2024-25.
That matters because later years include more schools and many more tested students. The 2024-25 nonpublic results are not simply the same set of schools retested five years later.
This expansion is important context, especially in the years following the launch of Iowa’s Students First Education Savings Account program. More students and more schools appearing in the data can affect year-to-year comparisons, even when the overall proficiency rate remains strong.
The Main Takeaway
The clearest takeaway is that Iowa’s nonpublic schools continued to post higher proficiency rates than public schools on ISASP results across the five school years reviewed. That advantage appeared in English language arts, math, and science, and it remained visible in every comparable year.
The size of the gap changed over time. Public schools improved more from 2020-21 to 2024-25, which narrowed the difference in each subject, while nonpublic schools started from a higher baseline and remained relatively steady.
The nonpublic data also changed in an important way because the number of schools and students included in the files increased substantially beginning in 2023-24. That means the later years reflect a larger testing universe, which should be kept in mind when comparing results across the full five-year period.
For parents, this kind of information matters because school choice is not only about where a child attends school. It is also about understanding how different schools and sectors are serving students academically, then using that information alongside other factors such as school culture, safety, values, class size, location, and student support.
No single assessment can tell the whole story of a school. Still, proficiency data can give families one more useful point of comparison as they consider the educational environment that best fits their child.
Taken together, the data show two things at once: nonpublic schools remained ahead in overall proficiency, and public schools made larger gains from a lower starting point. For Iowa families, that reinforces the importance of having access to clear information and meaningful educational options.