Media assets

Two acts.
One clear warning.

Downloadable graphics from the interactive story for Making hidden biases visible in population location data from mobile phones. Credit: Cabrera & Rowe / DEBIAS.

Lead and Act I

Correlation can hide uneven local coverage.

Social card comparing Watford and North East Derbyshire, with similar census populations but a 6.7-fold difference in Meta active-account rates — Lead news card · 1200 × 630Download PNG

Comparison of Watford and North East Derbyshire — 1 · A revealing pairDownload SVG

Scatter plot of census population and Meta estimate — 2 · The counts line upDownload SVG

Strip plot of local Meta coverage rates — 3 · Local rates varyDownload SVG

Map of local departures from the fitted Meta rate — 4 · The difference is localDownload SVG

Act II · Cross-source proof

The source changes the local picture.

The fitted-rate fingerprint shows the same pair switching sides; the 300-of-331 graphic shows that the pattern is widespread across England and Wales. Values are relative to separate source-specific fitted rates, not percentages of residents represented.

Watford and North East Derbyshire switching sides across four source-specific fitted rates — 5 · Four-source fingerprintDownload SVG

Unit chart showing 300 of 331 local authorities changing sides across source-specific fitted rates — 6 · 300 of 331 authoritiesDownload SVG

Act II · Crops from the accepted model figure

Different area contexts. Different nonlinear shapes.

These are illustrative, feature-level examples—not source-wide signatures. Each point is a local authority. The x-axis is a standardised area characteristic and the y-axis is its SHAP contribution to predicted coverage bias. The panels do not show the age, qualifications or inclusion probability of individual users. Compare shapes, not magnitudes.

Branded crop from the accepted SHAP figure showing an illustrative S-shaped area-level association between local share aged 20 to 29 and modelled Twitter/X coverage bias. — Twitter/X · age structure · illustrative S-shapeDownload PNG

Branded crop from the accepted SHAP figure showing an illustrative curved, reversing area-level association between population density and modelled Meta coverage bias. — Meta · population density · illustrative curved reversalDownload PNG

Two acts.One clear warning.

Two acts.
One clear warning.