AlleSchools

Data & methodology

Where does the data come from, and how is the chart calculated?

Secondary and primary schools use different sources and definitions. Both are explained separately; the indicators do not form a ranking.

Secondary schools (VO)

Data used

DUO school and branch records, annual exam candidate and pass counts, and VWO central-exam subject averages. International schools are outside the current scope.

X: VWO graduates as a share of all exam candidates

X = Σ(wᵧ × 100 × VWO passedᵧ ÷ all candidatesᵧ) ÷ Σwᵧ

Recent school years receive more weight. X describes graduate composition, not overall teaching quality or admission probability.

Y: central-exam index for the selected VWO profile

  • NT: 0.50×Mathematics B + 0.25×Physics + 0.25×Chemistry
  • NG: 0.35×Biology + 0.25×Chemistry + 0.40×Mathematics B
  • EM: equal weights for Economics, History and Mathematics A/B
  • CM: equal weights for History, Mathematics C/A and English/German/French

A school-year profile is omitted when a required subject is missing. Valid years are combined with time weights.

Dot size

Weighted average annual exam candidates over the five-year window; it represents sample size.

VO limitations

Results depend on subject choice, population and sample size. A missing required profile subject is omitted, not forced to zero. No single indicator measures overall school quality.

Primary schools (PO)

Data used

DUO primary-school advice and school records, plus CBS mean residential WOZ by four-digit postcode (PC4).

Did you know?

School advice and nearby home values often move together. This does not imply causation: family background, school choice, peers and neighbourhood resources may influence both.

X: VWO-equivalent advice share

X = 100 × (VWO + 0.5×HAVO/VWO + 0.1×HAVO) ÷ all advised pupils

This transparent exploratory conversion describes advice composition, not final enrolment.

Y: mean WOZ for the school’s PC4 postcode

CBS residential WOZ values are expressed in thousands of euros. Downloads currently cover 2019–2025; the current calculation window uses 2019–2024.

Exact-year values are preferred. A missing PC4-year uses its nearest available year and receives woz_imputed. has_full_woz is true only when every contributing year is exact.

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Total pupils receiving school advice in the calculation window.

PO limitations

Recent years receive more weight. Schools below sample thresholds are excluded; suppressed or missing CBS values are not real zeros. WOZ describes an area, not an individual family.

How to use this

Use the chart to ask questions and narrow a search, then combine it with official inspection reports, school information and visits. AlleSchools is not affiliated with DUO, CBS or the Dutch government.