Overview
The dashboard's figures are derived from the e-Stat Population Census (Statistics Bureau, Ministry of Internal Affairs and Communications), National Land Numerical Information (Ministry of Land, Infrastructure, Transport and Tourism), the Tokyo Metropolitan Government's regional earthquake risk survey, land use survey and 「高潮浸水想定区域図」 (storm surge inundation map), and the area survey of prefectures and municipalities (Geospatial Information Authority of Japan); the station list on the 「交通」 tab also shows figures from 「東京都交通局 乗降者数情報」 (the Tokyo Metropolitan Bureau of Transportation's passenger figures, from the Public Transportation Open Data Center). Below a panel that shows figures, a line starting 「出典」 names their source.
The source line
The source line gives the name of the source and the year or edition of the data. On the population panels, the source line starts 「出典：政府統計の総合窓口(e-Stat)（https://www.e-stat.go.jp/）」.
Data states
While data is loading, 「読み込み中」 is shown in place of figures. When data could not be fetched, 「取得失敗 — 時間をおいて再読み込みしてください」 is shown with the name of the source that did not answer. A figure that could not be fetched is never replaced with another value. When only the Population Census 5-year population change could not be fetched, only the change figures read 「取得失敗」; population, density and age structure are still shown. A value the statistics do not publish is shown as 「データなし」, not 0.
The source section at the bottom of the page
At the bottom of the dashboard, 「データ出典 / Data sources」 lists, under the heading 「実データ」, the source and credits of each dataset on screen. The row for each dataset, such as population, land price, zoning, transport and hazard, appears once that data has loaded; no row is shown for data that is loading or could not be fetched.