01 / THE EVIDENCE
Empirical field inference
Explore the changing geography of six everyday expressions.
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Inferred MAP frequencies1950
195019601970198019902000
Preparing data…4,000 research cells
Change across birth cohorts
Population-weighted frequencies among the included variants.
HOW TO READ THIS MAP
Estimates, not a census.
The maps show precomputed maximum a posteriori (MAP) frequency estimates from the research repository. A Bayesian Gaussian process smooths survey evidence over space and time. Frequencies sum to one across the included variants; rarer alternatives are excluded.
The year is the respondent’s birth year. Under the apparent-time assumption, speakers’ responses approximate the language of their community during adolescence. These are not repeated surveys conducted in each displayed year. Posterior uncertainty intervals are not provided in the supplied field arrays.