Question
UrbanOracle's dashboard mixes live data and sample data. With a ward selected, where does a census value appear as live data for every ward, and what is shown there?
Method
- Product and screen: UrbanOracle's dashboard,
/app. We chose a ward in the ward selector and opened the 「人口」 (population) tab. - Scope: all 23 wards listed in the selector.
- What was recorded: the 「人口」 (population), 「成長率」 (growth rate) and 「高齢率」 (elderly share) cards and the 「年齢構成」 (age composition) block of the 「人口」 tab with a ward selected. As far as the code shows, this is the view that gives live census data for every ward.
- Checking that the data is live: whether a view is live or sample is decided on each page load. Right after loading, sample values appear with sample labels; they switch when the fetch completes. Before recording, we checked the source label in the age composition block and that the census line was listed under 「実データ」 (live data) at the foot of the page, and we recorded that label for each ward.
- All wards in one page load: data is fetched once per page load and is not fetched again when the ward or tab changes. All wards were recorded within the same load.
- How it was recorded: for each ward we recorded the text on the screen, the list at the foot of the page and an image of the screen. Ward names are written as the product displays them, with a plain transliteration added by the author.
- Date and production revision: 2026-10-13. Cloud Run revision
urbanoracle-00016-thf(commiteeee5cc). The revision was the same before and after the measurements. The results are the output of the production revision at that time.
Where the values come from was confirmed by reading the code at that commit.
- Population and age: statistical table
0003448299, fetched through the e-Stat API. - Growth rate: read as is from statistical table
0004050417. The product does not compute it from population counts. - Young and elderly shares: the table's percentage, rounded to an integer.
- Working-age share: the remainder, 100 − young − elderly.
- 「23区平均」 (ward average) values are not published: the figures shown on the right-hand side of the age composition block and as 「平均」 (average) under the cards are not values from the statistical tables; they are plain means of the ward values, computed in the browser. For the age shares they are means of ward percentages that have already been rounded to integers. Since they are not census values, this note leaves them out, as it does the 「密度」 (density) card below.
- When the fetch fails: there is no error screen; sample values are shown with the sample label.
- Cache: a live result is kept on the server for 24 hours.
The 「密度」 (density) card is not published here: it is population divided by ward areas whose origin is not recorded.
Results
The cards of the 「人口」 tab with a ward selected, as displayed.
| Ward | 人口 (population) | 成長率 (growth rate) | 高齢率 (elderly share) |
|---|---|---|---|
| Setagaya (世田谷区) | 94.4万 | +1.4% | 20% |
| Nerima (練馬区) | 75.3万 | +1.2% | 22% |
| Ota (大田区) | 74.8万 | +1.5% | 23% |
| Edogawa (江戸川区) | 69.8万 | +1.0% | 21% |
| Adachi (足立区) | 69.5万 | +1.1% | 25% |
| Suginami (杉並区) | 59.1万 | +1.1% | 21% |
| Itabashi (板橋区) | 58.4万 | +1.8% | 24% |
| Koto (江東区) | 52.4万 | +5.5% | 21% |
| Katsushika (葛飾区) | 45.3万 | +3.2% | 25% |
| Shinagawa (品川区) | 42.2万 | +0.9% | 20% |
| Kita (北区) | 35.5万 | +3.7% | 25% |
| Shinjuku (新宿区) | 34.9万 | +3.5% | 20% |
| Nakano (中野区) | 34.5万 | +3.0% | 20% |
| Toshima (豊島区) | 30.2万 | +1.5% | 20% |
| Meguro (目黒区) | 28.8万 | -0.6% | 20% |
| Sumida (墨田区) | 27.2万 | +4.8% | 22% |
| Minato (港区) | 26.0万 | +4.7% | 17% |
| Shibuya (渋谷区) | 24.4万 | -2.0% | 19% |
| Bunkyo (文京区) | 24.0万 | +4.1% | 19% |
| Arakawa (荒川区) | 21.7万 | +4.1% | 23% |
| Taito (台東区) | 21.1万 | +8.0% | 23% |
| Chuo (中央区) | 16.9万 | +7.5% | 15% |
| Chiyoda (千代田区) | 6.7万 | -0.7% | 16% |
The 「年齢構成」 block, as displayed.
| Ward | 年少 (young) | 生産 (working age) | 高齢 (elderly) |
|---|---|---|---|
| Setagaya (世田谷区) | 12% | 68% | 20% |
| Nerima (練馬区) | 12% | 66% | 22% |
| Ota (大田区) | 11% | 66% | 23% |
| Edogawa (江戸川区) | 13% | 66% | 21% |
| Adachi (足立区) | 11% | 64% | 25% |
| Suginami (杉並区) | 11% | 68% | 21% |
| Itabashi (板橋区) | 11% | 65% | 24% |
| Koto (江東区) | 13% | 66% | 21% |
| Katsushika (葛飾区) | 11% | 64% | 25% |
| Shinagawa (品川区) | 12% | 68% | 20% |
| Kita (北区) | 10% | 65% | 25% |
| Shinjuku (新宿区) | 9% | 71% | 20% |
| Nakano (中野区) | 9% | 71% | 20% |
| Toshima (豊島区) | 9% | 71% | 20% |
| Meguro (目黒区) | 11% | 69% | 20% |
| Sumida (墨田区) | 10% | 68% | 22% |
| Minato (港区) | 14% | 69% | 17% |
| Shibuya (渋谷区) | 11% | 70% | 19% |
| Bunkyo (文京区) | 13% | 68% | 19% |
| Arakawa (荒川区) | 11% | 66% | 23% |
| Taito (台東区) | 9% | 68% | 23% |
| Chuo (中央区) | 14% | 71% | 15% |
| Chiyoda (千代田区) | 14% | 70% | 16% |
The source label of the age composition block recorded on each ward's screen appeared in 1 form.
| Line as displayed | Wards |
|---|---|
| 出典: e-Stat 国勢調査（総務省統計局） ／ 2020年国勢調査・2025年速報 ／ 単位: % | 23 |
Reading the results
- Kind of display: on all 23 wards the source label of the age composition block was the same single line (1 form) and was not a sample-data label. In all 23 readings the list under 「実データ」 (live data) at the foot of the page included the line 「人口・密度・増減・年齢構成（人口タブ・区別テーブル・成長率指標）: e-Stat 国勢調査（総務省統計局） 2020年国勢調査・2025年速報」.
- Population (人口): from 94.4万 (Setagaya) down to 6.7万 (Chiyoda). 「万」 means ten thousand.
- Growth rate (成長率): from +8.0% (Taito) down to -2.0% (Shibuya); 3 wards showed a negative rate (Meguro, Shibuya, Chiyoda).
- Elderly share (高齢率): from 15% (Chuo) to 25% (Adachi, Katsushika, Kita). The card showed the same value as 「高齢」 in the age composition block on all 23 wards.
- Age composition (年齢構成): the young share ran from 9% to 14% and the working-age share from 64% to 71%. Young, working-age and elderly added up to 100 on every ward, which matches the calculation described above, where the working-age share is the remainder.
- These are the values UrbanOracle displayed at the time of measurement. To check the statistical tables themselves, see the e-Stat tables listed under Sources.
Limits
- Only the per-ward view of the 「人口」 tab was recorded. The land price, disaster, transport and zoning panels show, per the code, sample data or data whose origin is unconfirmed, and were left out.
- Live or sample is decided on each page load. This record is the result of 1 page load.
- The shares are integers rounded by the product, and the working-age share is computed as a remainder, so the last digit can differ from the statistical table.
- The growth rate comes from a preliminary tabulation.
How to reproduce
- Sign in to UrbanOracle and open
/app. - Wait until the census line appears under 「実データ」 at the foot of the page.
- Choose a ward in the selector and open the 「人口」 tab.
- Read the cards and the 「年齢構成」 block. Change the ward and repeat.
Data attribution
- Source: Portal Site of Official Statistics of Japan, e-Stat (https://www.e-stat.go.jp/). The figures shown are values that UrbanOracle fetched from Population Census tables (Statistics Bureau of Japan) and processed (rounding, remainder) for display.
- UrbanOracle uses the API function of e-Stat, but the content of the service is not guaranteed by the Japanese government. The notice in the original wording: 「このサービスは、政府統計総合窓口(e-Stat)のAPI機能を使用していますが、サービスの内容は国によって保証されたものではありません。」
- See the UrbanOracle documentation; where each DXA Labs product gets its data is summarised in Data sources and measurements (Japanese).