Census and Household Surveys: Locating Every Dwelling

A good survey depends on knowing exactly which dwelling was visited. In many areas houses have no number, streets have no name, and two enumerators describe the same compound in different words. The result is duplicates, missed households and follow-up visits that cannot find the original respondent. A UPCS code gives each dwelling a precise reference: it takes anyone who opens it to the exact spot that was picked, a 3 m x 3 m square.

The enumeration problem

Teams usually work from sketch maps and paper lists. Settlements grow faster than the maps do, new structures appear between mapping and fieldwork, and a "block" on paper can hold dozens of lookalike rooms. Supervisors who audit work, or return teams who must re-contact a sample household, need more than "third door on the left".

Coverage errors usually start before the interview: unclear boundaries between assignment areas, outdated listings and overlapping assignments lead to some households being counted twice and others never reached. A precise reference for each dwelling makes both problems visible.

How codes fit the workflow

At each dwelling, the enumerator opens the UPCS map, zooms until the grid shows and picks the main entrance. The resulting code is written into the questionnaire next to the household ID. A supervisor, back-checker or later survey wave opens the code and arrives at that exact doorway.

Since a code is derived from the cell, two different teams picking the same entrance get the same code. This makes duplicate detection easy: matching codes point to the same place.

Practical set-up

• Field staff: search box or upcs.io/<code> to find a previously recorded household.
• Supervisors: build the check-list from codes so back-checks go to exact doors.
• Your data system: POST /v1/upcs/generate with latitude and longitude returns the code and a share link for each record; GET /v1/upcs/lookup/{code} returns coordinates and map links. Details are in the documentation.
• Custom collection tool: embed the map and use the onSelect payload (code, coordinates, address, share link) as fields in your form.

Tips for consistent picking

1. Fix one rule for every team, for example the main entrance of the structure where people sleep.
2. For compounds with several dwellings, pick each dwelling door separately.
3. Zoom to the grid level before tapping, so the point is the entrance rather than the street.
4. Store the code, not only a description, so later waves can navigate straight there.

UPCS is not an official census product and does not claim any link with national statistics offices; it is simply an exact-location code that your own survey process can store. See also market research and field surveys and surveying and mapping teams.