Iowa City Schools — Enrollment Forecast

Base year: 2025 actual = 14,227 students (Iowa DOE BEDS).

High: growth corridors strengthen; effective K-entry share rises to 0.740.   Baseline: share holds at 0.728 (current).   Low: in-migration decelerates; effective share falls to 0.680.

Three independent organizations — the Iowa DOE, Woolpert / Cooperative Strategies (hired by ICCSD in early 2025), and this cohort-survival model — used different methods and data to project enrollment. Their 2030 numbers differ by a few hundred students, but all three agree on the direction and the scale of the expected decline.

Year-by-year comparison

What the convergence means: The Iowa DOE and this model land within 245 students of each other at 2030 using completely independent methods — the state's demographic model versus a birth-lag cohort-survival approach. Woolpert runs about 570 students higher at 2030 but continues declining; at its current rate it reaches the same range by 2031–32. All three agree enrollment will fall and reach the mid-13,000s during this decade. That directional consensus is the meaningful signal — not any single number.

Sources: Iowa DOE District Enrollment Projections 2026–27 to 2030–31 (certified enrollment basis); Woolpert / Cooperative Strategies Demographic Analysis presented to ICCSD Board, Feb 2025 (headcount basis); this model (BEDS K–12, see methodology page).

All three scenarios use the same declining birth trend. What differs is the assumption about how many of those babies eventually walk through Iowa City's school doors.

For the full methodology, worked examples, and the math behind each scenario: How this model works →

All rows are verified Iowa DOE BEDS fall enrollment counts from the district's October 1 headcount, school years 2016-17 through 2025-26. Green tag = BEDS actual. COVID disruption years 2020 and 2021 are flagged; 2023 is marked because K-share trends shifted starting that year.

A rate above 1.0 means the cohort grew going into the next grade (students transferring in or new families arriving). The 8th-to-9th transition consistently shows a gain as students from smaller schools consolidate into Iowa City High and West High. Rates below 1.0 reflect attrition — the 9th-to-10th and 10th-to-11th transitions typically show small losses. All rates computed from verified Iowa DOE BEDS data.

Kindergarten is modeled from Johnson County resident births lagged five years, scaled by the ICCSD effective share (0.728). This share is calibrated from the 2025 BEDS actual (K=987) against 2020 Johnson County births (1,356): 987/1356 = 0.728.

Observed trend since 2023: The kindergarten count has declined three straight years (1,035 → 998 → 992 → 987 from fall 2022 through fall 2025). The effective district share of county births fell from a 2016–2022 average of 0.742 to a 2023–2025 average of 0.718. The cause of this shift has not been established — multiple factors interact (births, migration, open enrollment, private-school choice). The three scenarios bracket the range of how this share might evolve.

All historical K values from Iowa DOE BEDS (verified). Share = actual K ÷ Johnson County births 5 years prior. 2016–2022 avg share (excl. COVID 2020): 0.742. 2023–2025 avg share: 0.718. Cause of shift unknown.

Geography caveat: Johnson County births overstate the ICCSD-relevant pool because the district boundary does not equal the county line. The 0.728 share corrects for this and also reflects any structural factors (open enrollment, private-school choice, migration) that currently affect district enrollment.

ICCSD's kindergarten share of Johnson County births has shifted since 2023. What the data shows clearly:

• The 2016–2022 average share (excluding COVID) was 0.742. The 2023–2025 average is 0.718 — a decline of about 0.024 percentage points.
• The North Liberty and Tiffin corridors — both partly inside ICCSD boundaries — are among the fastest-growing areas in Iowa. New housing drives in-migration of families with young children, adding K-entry demand independent of the birth trend.
• Multiple factors simultaneously affect the share: the district boundary doesn't match the county line, families can open-enroll across district lines, some choose private schools, and migration adds or removes families.

What the data does not tell us is why the share changed. Coincidence of timing with any particular event is not evidence of causation. Attributing the shift to any single factor would require enrollment-transfer data we do not currently have. The three scenarios are designed to bracket the range without asserting a cause.

Building-permit data from North Liberty, Tiffin, and Coralville should be added as a leading indicator — a quarterly permit series predicts K entry about 5–6 years ahead and would help separate migration effects from enrollment-choice effects.

The detail behind each factor. We have measured the individual forces on enrollment in separate analyses: county demographic growth, Clear Creek Amana and Tiffin geographic capture, ESA private-school transfers, and open enrollment.
What's driving ICCSD enrollment? Factor decomposition, 2011 to 2026 →
Is ESA draining ICCSD enrollment? Voucher decomposition →
What the decline costs: enrollment to revenue bridge →
Building permits as an early enrollment signal →

1. Backtest. Fit GPRs on data through 2020 and predict 2021–2025 actuals. Target: MAPE ≈ 1–2% at year 1, widening to 4–5% at year 5. This validates the smoothing weights before relying on the 2030 range.
2. Corridor building permits. Add a quarterly permit-count series from North Liberty, Tiffin, and Coralville as a leading indicator for K-entry in the High and Baseline scenarios — residential permits predict enrollment about 5-6 years ahead.
3. Open-enrollment in/out. Iowa DOE publishes annual district-level open-enrollment flows. Adding these separates in-district retention from cross-district transfers and improves GPR attribution.
4. Private-school and open-enrollment data. Iowa DOE open-enrollment in/out flows by district are published annually. If recipient-level enrollment data by district of residence also becomes available, it would allow direct measurement of private-school enrollment shifts rather than inferring them from the K share trend.

Rebuild every December when the new October BEDS file is released. Steps:

1. Download the new Iowa DOE BEDS grade-level export (Iowa DOE Student Reporting in Iowa).
2. Add the new year's grade vector to BEDS_ACTUAL in the script.
3. Update BIRTHS with the latest CDC WONDER Johnson County natality data.
4. Recalibrate ICCSD_COUNTY_SHARE from the new K actual vs. lagged births.
5. Run python3 scripts/build_enrollment_forecast.py.

• Grade-level enrollment (BEDS actual, all years): Iowa DOE Student Reporting in Iowa fall enrollment files for school years 2016-17 through 2025-26, Iowa City Community School District K-12 headcount by grade, October 1 count date. Downloaded 30 June 2026.
• Johnson County births: CDC WONDER natality data, final through birth year 2022; estimated for 2023-2024. Lag 5 years to K entry year.
• Statewide program context: Iowa Department of Education (statewide Educational Savings Account enrollment counts, 2023–25).
• State projection benchmark: Iowa DOE District Enrollment Projections 2026–27 to 2030–31 (developed May 2022). Use as comparison baseline, not as a forecast.