Why these sizes?

PPS’s size goal is more than 360 students for each elementary school, more than 500 for each middle and K-8 school, and more than 1,100 for each high school (PPS Family Guides, glossary, p. 2). Where do those numbers come from, and how many schools fall short?

• 360 and 500 come from the state’s Quality Education Model. Oregon uses an average 360-student elementary and 500-student middle school to estimate what an adequate education costs. The state calls them “composites representing an average school” (QEM Report 2026, p. 91), and the Legislature’s research office notes that “Schools in Oregon are not required to adhere to the model’s components” (LPRO issue brief, Dec. 2023, p. 2).
• PPS uses them as floors. An outside equity audit PPS commissioned (SEGC equity audit evaluation report, June 2026, reviewing PPS’s Southeast enrollment-balancing work) called the state numbers a “minimum adequacy floor” but not “a final enrollment target” (p. 143). It suggested higher planning floors, about 450 elementary, 600 middle and 650 K-8 (pp. 144–145), and said even those “should not be used as automatic closure thresholds” (p. 145).
• 1,100 for high school is PPS’s own number, from its Jefferson dual-assignment work (PPS board memo, Aug. 4, 2026, p. 2). The state model’s high school has 1,000 students (QEM Report 2026, p. 91).

Bigger schools cost less per student, up to a point

What Oregon schools spent per student, by school size. Cost per student falls steeply as schools grow from very small, then flattens out. The shaded band is the size range the state’s cited research calls effective; the blue line is PPS’s threshold.

Source: Oregon Department of Education, The Costs of Operating Small Schools in Oregon (2002), Table 5 (printed p. 9, PDF p. 13): non-transportation operating spending per student by school size, every Oregon school, 2000-01, including district and ESD costs. Dollars are 2000-01 dollars, so read the shape, not the level. Each point is a size group (for example 351–500 students) drawn at its middle; the open-ended “greater than 2,000” high school group is placed at 2,250 for display. The large blue dot sits where PPS’s threshold crosses the line (360 elementary, 500 middle, 1,100 high): a value read from the line between the two nearest size groups, not a reported figure. Statewide, not PPS: for a PPS-specific view, see a community site’s reconstruction of PPS’s staffing formula (Right Size Portland); PPS hasn’t published the formula itself. The shaded range comes from studies of student learning, not from this cost data (see Research ranges below). The state model school is the average-size school Oregon uses to estimate what an adequate education costs: 360 elementary, 500 middle, 1,000 high (QEM Report 2026, p. 91); schools are not required to match it.

Where the numbers come from

For each level: the size range the state’s cited research calls effective, the state’s model school, PPS’s threshold, and the floor PPS’s equity audit suggested.

Research ranges: Cotton (1996), the synthesis the state model cites, for elementary (300–400) and middle (400–800); Lee & Smith (1997) for high school (600–900). There is no state K-8 model school; PPS reused 500. The state’s elementary model school was 340 students until at least 2018 and is 360 from 2022; no report says why.

What the state model is

“The prototypes do not represent any actual schools but are composites representing an average school for its category. A research synthesis conducted by Education Northwest indicates that an effective size for elementary schools is between 300-400 students and that middle schools that are effective range from 400-800 students. The ideal high school is between 600-900 students.”Quality Education Commission, QEM Report 2026, p. 91

The model prices an adequate education at “efficiently-scaled” schools (2026 report, p. 92). It is a funding benchmark: “Schools in Oregon are not required to adhere to the model’s components” (Legislative Policy and Research Office, issue brief, Dec. 2023, p. 2). Its own 2024 report says the model schools “no longer fully account for the diverse conditions and communities present across Oregon” (QEM Report 2024, printed p. 18, PDF p. 20), and an outside evaluation found their sizes rest on “decades-old research estimates” (LPRO summary of the AIR evaluation, Oct. 2025, p. 8).

Source: QEM Report 2026, “Prototype schools,” p. 91. Oregon law’s only school-size line, ORS 327.077, gives extra funding to remote small elementary schools and to small high schools in small districts; PPS schools don’t qualify. There is no state minimum school size.

How many schools fall below

Every neighborhood school, by enrollment. A dot is red if it is below the line you choose, green if at or above.

Why PPS says size matters

PPS’s case is about staffing: with too few students, schools blend grades, share specialists and cut electives.

“Maintaining more than 80 school sites amid declining enrollment has spread resources increasingly thin. Schools experience this through blended classrooms, an increase in itinerant staff, reduction in school-wide supports such as counselors or social workers, or courses being offered in alternate years.”PPS board memo, “Rightsizing Update: Equity Audit Evaluation,” Aug. 4, 2026, p. 2 (BoardBook)

PPS’s “well-resourced schools” definition lists “2-3 sections per grade” for K-5 and “6-8 sections per grade” for middle school (Sept. 8, 2026 deck, slide 7, “Sustainability thresholds by grade band”). The arithmetic behind the numbers:

Six grades for K-5, three for middle school. This is arithmetic, not evidence about outcomes; PPS hasn’t published the staffing formula that ties enrollment to specialists.

What the research says, and doesn’t

• Studies mostly give ranges where schools tend to work well, often upper limits, not a size below which a school fails. Cotton (1996): “an appropriate and effective size is 300-400 students for an elementary school and 400-800 students for a secondary school” (Education Northwest, summary, PDF p. 11).
• Leithwood & Jantzi (2009), a review of 57 studies, favors smaller schools: elementary schools of no more than about 300 (high-need) to 500 students, secondary schools of no more than about 600 to 1,000. This is from the article’s ERIC abstract; the full article was not read.
• In Oregon, per-student costs rise steeply only for very small schools: below about 100 students for elementary and 300 for high school (ODE, The Costs of Operating Small Schools in Oregon, 2002, printed p. 1).
• PPS’s equity audit: effects of size on achievement are “mixed, modest, and highly dependent on context” (p. 142). Smaller schools “often provide stronger relationships”; larger ones “often provide more staffing flexibility, more program breadth” (p. 141).

Floors or goals?

“PPS should consider Oregon’s QEM as an adequacy benchmark, but not as a final enrollment target.” … “PPS should treat QEM as a minimum adequacy floor rather than a complete contemporary model of what every well-resourced school requires.”On the state’s numbers: PPS’s equity audit of the Southeast enrollment and program balancing work, June 10, 2026, p. 143 (report)

“Moreover, we cannot state enough that these numbers should not be used as automatic closure thresholds. They should be used as planning ranges to assess whether schools are likely to remain large enough over the next five or so years to sustain the staffing, programming, class size, and student support conditions associated with however PPS describes well-resourced schools.”On the audit’s own suggested floors (450 elementary, 600 middle, 650 K-8): the same report, pp. 145–146

“School size goal: More than 360 students for K-5 schools; more than 500 for K-8 or middle schools; more than 1,100 for high schools. These are planning goals, not ratings of school quality.”PPS Family Guides, glossary, p. 2

“So these are numbers that we’ve settled on. Again, not ideal state, but it’s a bridge.”PPS staff, Oct. 6, 2026 board meeting (video, 1:38:37)

The audit’s higher floors add a five-year enrollment-loss buffer to the state numbers (360 + about 85; 500 + about 100; pp. 144–146). It says schools below them “may still be necessary, valued, and educationally strong” (p. 146). Switch the chart above to “Audit floor” to see how many schools fall below it.

The Oregon guidance

• Quality Education Model reports (Oregon Department of Education)
• QEM Report 2026 (model schools, p. 91) · QEM Report 2024
• Legislative Policy and Research Office: QEM issue brief (Dec. 2023)
• LPRO summary of the AIR evaluation of the QEM (Oct. 2025)
• Quality Education Commission slides naming the model schools (2023)
• ORS 327.077, small-school funding
• ODE: The Costs of Operating Small Schools in Oregon (2002)

Research notes with every quote and page number: RESEARCH.md. Chart style inspired by the community site Right Size Portland.