Methodology

What observed, estimated, calculated, derived, and modelled mean

Every production layer carries a data-nature label: observed, modelled, calculated, or derived. Estimated is not a fifth layer nature. On derived layers such as Estimated Literacy Rate, each country value is tagged reported or estimated. The labels describe how the figure was produced, not how complete or how “good” a country is.

Two different labels

OurBlueDot uses a layer data nature on every indicator: observed, modelled, calculated, derived, or, for interface fixtures, demonstration. That label is shown on layer pages, country-layer pages, the country panel, country profiles, and the sources catalogue.

Estimated is not a layer data nature. It is a per-value tag used on derived layers. On Estimated Literacy Rate, each country figure is labelled reported (UNESCO/WDI literacy) or estimated (an OurBlueDot estimate). Those tags appear next to the number. They do not replace the layer nature, which remains derived.

Observed

Observed means the atlas treats the published country values as source observations or source-compiled statistics. GDP per capita is World Bank WDI current US dollars. GDP per capita in Finland is therefore classified as observed data. Ember generation terawatt-hours and Global Carbon Budget territorial CO₂ per person are also treated as observed: they are compiled national statistics, not OurBlueDot models.

Observed does not mean complete UN-193 coverage, absence of any modelling inside the original statistical system, or a survey microdata download. It does not mean the figure is a welfare score. Missing observed countries stay missing.

Users encounter this label on economy and several environment and mobility layers, including Happiness life-evaluation scores from the World Happiness Report Figure 2.1 extract.

Modelled

Modelled means the atlas republishes source-modelled estimates. PM2.5 Exposure is population-weighted modelled annual exposure, not a city air-quality index and not a station reading. PM2.5 exposure in India is classified as modelled data. Employment Rate, Female Labour Force Participation, electricity and clean-cooking access, internet users, life expectancy, fertility, child and maternal survival, alcohol consumption, adult obesity, and temperature change are modelled for the same reason: the imported series is a model output, and the redistribution path does not expose a usable observed-versus-imputed flag for each row.

Modelled does not mean OurBlueDot fitted the model, that the value is a forecast, or that a missing country may be filled with zero. Modelled gaps remain grey. A modelled 100 percent access figure in a high-income country can still include a source assumption; that is documented on the layer, not upgraded to “observed.”

Calculated

Calculated means the country value is produced from a stated formula and inputs inside the atlas. Day length uses date, latitude, solar declination, and a standard sunrise/sunset altitude at each UN member’s representative coordinates. Day length in Norway is classified as calculated data. The figure is a photoperiod estimate for that location and date, not an observed weather record and not a civil timetable.

Calculated does not mean measured at a meteorological station, and it is not a quality verdict. Calculated layers are treated as descriptive: a longer or shorter day is not better or worse.

Users encounter this label on the Earth & Space hub, currently for day length.

Derived

Derived means the indicator combines published source series under an auditable hierarchy. Estimated Literacy Rate is the current derived layer. Tier 1 is UNESCO/WDI adult literacy. Where that is unavailable, OurBlueDot may supply a labelled estimate. Users can see which rule produced the number.

Derived does not mean unofficial data were substituted silently, and it does not turn estimates into official surveys. The Education hub exists so this series can be read as an education indicator without hiding the derivation.

Users encounter derived on the literacy layer page, which carries an explicit banner, and on country pages such as literacy in Finland.

Estimated

Estimated, on this atlas, is a country-value label on a derived layer. It means OurBlueDot produced the figure from the published derivation rule, with a confidence label. Reported means the cell is a UNESCO/WDI literacy value (including a labelled snapshot carry of an earlier UNESCO observation when the 2024 map uses a previous observation year).

Estimated does not mean the layer nature is “estimated,” does not mean the value is a UNESCO official survey, and does not mean modelled layers such as PM2.5 or employment are “estimated” in this sense. Those layers stay modelled. Demonstration layers are a separate status: they validate the interface, are labelled demo, and are excluded from indexing.

This does not measure

Data nature is not a league table of source quality, not a claim that observed beats modelled, and not permission to treat a map as complete. Each layer still has its own definition, period, unit, and gaps. Read the layer methodology for the indicator; use this page only for the shared vocabulary.

Continue in the atlas

These pages are the working examples for this question. They are not a complete catalogue.

Related atlas concepts

Other Insights pages that explain shared atlas behaviour, not a reading list of articles.