5. Inputs and Evidence Sources

The methodology draws on the following categories of inputs.

5.1 Provider Published Price Data

The only input to the pricing and availability scores is each provider's own published price list. For each provider, the methodology team reviews the structure of the published list, establishes which fields carry the on-demand price and the unit it is quoted in, and maintains the translation of that provider's list into the common shape the scoring operates on. That translation work is provider-specific and is revised when a provider changes the structure or the field semantics of its published list.

No other price evidence is used. The chain contains no customer billing data, no telemetry, no survey input, and no third-party price aggregator. The source is public for every provider in scope, so the inputs to a pricing or availability score are independently reachable.

The published lists carry occasional errors that survive into the raw input. The most consequential is an entry whose value is not the per-unit price for the unit stated on the entry, for example a multi-year commitment total appearing in a field the list defines as an hourly rate. An entry of that kind holds a different quantity from the one its field claims, and it would distort any statistic computed over the product category it belongs to. Section 6.2 describes how such entries are identified and removed. The pricing score therefore uses medians throughout in place of means, as a median is insensitive to a small number of extreme values in a way a mean is not.

5.2 Grid Carbon Intensity Data

The carbon grade is built from hourly, region-specific grid carbon intensity factors produced by GPX Grid, Greenpixie's internal grid intensity tool. GPX Grid draws on a tiered hierarchy of national grid operator sources, modelled national datasets, and international averages, and accounts for the upstream and lifecycle emissions of the generating technologies and fuel types present on each grid. Its derivation, source hierarchy, and academic validation are set out in the Greenpixie Methodology for Cloud Emission Measurement, and this document does not restate them.

Each region is associated with the grid that serves its location, and the hourly factors for that grid are averaged into a single figure expressed in grams of CO₂e per kilowatt-hour, which is the value the carbon grade is assigned from. Grid carbon intensity moves through the day as demand rises and as wind and solar output changes, and through the year with the generating mix, so a single hourly value describes one hour on that grid and says little about the region. The average is taken over the previous calendar month, which absorbs the daily cycle but not the seasonal one.

No customer usage data enters the carbon grade. The grade describes the grid a region draws from, and the emissions of a workload running there are calculated per unit of cloud usage under the Greenpixie Methodology for Cloud Emission Measurement.

5.3 Baseline Water Stress Data

The water stress category is taken from Aqueduct 4.0, the water risk database published by the World Resources Institute and documented in the technical note listed in Section 12. The indicator used is Baseline Water Stress, being the ratio of total water demand to available renewable surface and groundwater supply in an area, expressed as a percentage and reported in five named categories.

Greenpixie applies no factor, weighting, adjustment, or recategorisation to a Baseline Water Stress figure, and publishes the category Aqueduct assigns to the area a region sits in. What Greenpixie contributes is the association between the two. Aqueduct reports at a finer geographic grain than a cloud region, together with country-level aggregations, so each region has to be matched to the Aqueduct area covering its location. Section 6.6 sets out how that match is made, when a country-level figure is used instead, and what happens where Aqueduct covers neither.

The World Resources Institute republishes Aqueduct on a cycle measured in years, so the water stress category changes far less often than the other three scores. Section 8 states the refresh cadence of each.

5.4 Data Versioning and Refresh

The inputs are refreshed and rescored monthly, and each run is identified by its data version. A region's pricing and availability scores describe the provider's catalogue as published at the time of that run, and its carbon grade describes the grid over the period that run averaged.

Providers change list prices, launch product categories, and extend their catalogues into newer regions between runs, and grids change as generating capacity is added and retired, so two data versions are not directly comparable, for the further reason given in Section 8.