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AI-Assisted Handwriting Transcription of the 1931 Canadian Census

Research & Development

What it collects that can identify you

Sensitive personal information
Identifiable data
  • Digitized images of the 1931 Canadian Census pages containing handwritten personal information about approximately 10 million individuals, including names, ages, addresses, occupations, and family relationships.

Also collects about a place, which is anonymized data.

Run by
Library and Archives Canada (LAC)
Where
No fixed location
Kept
Retained indefinitely
Shared with
Accountable organization, 3rd parties

What it is for

Research & Development

This system uses artificial intelligence and handwritten text recognition (HTR) to automatically read and index approximately 10 million names from digitized images of the 1931 Canadian Census. It was developed by Ancestry using proprietary AI, in partnership with FamilySearch, with digitized records provided by Library and Archives Canada. The resulting index is publicly accessible and allows Canadians to search for their ancestors in census records. Users should be aware that AI transcription may contain errors inherent to automated handwriting recognition.

What it collects and what happens to it

Data taken in

Sensitive personal information
Identifiable data
  • Digitized images of the 1931 Canadian Census pages containing handwritten personal information about approximately 10 million individuals, including names, ages, addresses, occupations, and family relationships.
About a place
Anonymized data
  • The 230,000 digitized census images are organized by geographic district and sub-district, providing locational context (addresses, municipalities, provinces) captured in the original 1931 census enumeration.

Processing

Classification & Prediction
  • The HTR system uses AI-based classification to recognize and label handwritten characters and words in census images, assigning each detected text region to a transcribed token. Ancestry's proprietary model was trained to classify handwriting from historical documents.

What it does

Sensing (Perceptive AI)
Human decides
  • The system reads digitized images of handwritten census pages and converts them into structured, searchable text. It applies handwritten text recognition (HTR) to sense and extract names and other census fields from approximately 230,000 scanned images.
Deciding (Analytical AI)
Human decides
  • Following transcription, the AI classifies and structures extracted text into index entries (names, dates, locations) that form a searchable database. Humans can review and correct the AI-produced index entries.

Outputs

Sensitive personal information
Identifiable data
  • The system produces a structured index of approximately 10 million names and associated personal details (age, address, occupation, family relationships) transcribed from the 1931 census, made publicly searchable online.
Operational data
Anonymized data
  • Aggregate index metadata and transcription records organized by census district, enabling archival and administrative use of the digitized census collection by Library and Archives Canada.

Run by

Library and Archives Canada (LAC)
  • Library and Archives Canada (LAC) is the federal institution accountable for this AI system. LAC provided digitized preservation assets (approximately 230,000 census images) and is responsible for the public deployment of the resulting index.

Census 1931 Index — AI Register entry 2526-LAC-BAC-008

Built by

Ancestry
  • Ancestry developed the proprietary handwritten text recognition (HTR) and AI system used to transcribe the census. FamilySearch partnered in the development. The AI technology and its outputs are governed by Ancestry's proprietary systems.

Census 1931 Index — AI Register entry 2526-LAC-BAC-008

Kept for

Retained indefinitely
  • The 1931 census index is a permanent archival record. As a historical genealogical dataset created from century-old census records, it is expected to be retained indefinitely as part of Canada's national archival heritage.
  • Duration: indefinitely

Shared with

Available to the accountable organization
  • Library and Archives Canada has access to the digitized census images and the resulting AI-generated index as the institution that provided the source assets and is accountable for the deployment.
Available to 3rd parties
  • The index is accessible to members of the public through Ancestry and FamilySearch platforms. As a genealogical record of historical (1931) personal data, access is broadly available, though Ancestry's proprietary platform may impose terms of service.

Stored

Not stated by the Helpful Places.

How to read the colours

Can it identify you?

Anonymized data
Data about people with the link to who is broken. Stripped of identifiers, blurred, aggregated, or noised so this system can’t reasonably tie a record back to an individual.
Pseudonymous data
Each person’s data is tied to a token (hash, ID, template) that lets this system recognise the same person across events, but the token itself doesn’t reveal a name. Reidentification is possible with extra information.
Identifiable data
The data either contains a direct identifier (name, address, account name, recognisable face or voice, plate number) or carries a token this system uses to look up legal identity during processing.

Who completes the loop?

Human decides
This mode suggests; a person decides what to do next. The AI is always advisory — a human is in the loop on every decision. Example: a triage tool ranks cases for a clinician who chooses which to see first.
Human executes
This mode decides; a person carries out the result. Example: an optimizer plans the day’s trash-collection routes, and drivers run them.
Autonomous
This mode decides and acts on its own. No person reviews each decision or carries out the resulting action.

Definitions from the DTPR standard. Amber is about your data, violet about who decides. The fuller the shape and the deeper the colour, the more identifying the data or the less a person is involved.

What you can do

Ask about this system

Questions go to the Helpful Places, not the vendor.

Your rights

  • Right to Algorithmic TransparencyUsers are informed that this index was created using AI handwritten text recognition technology. The AI Register entry for this system is publicly accessible, disclosing that AI use has been disclosed to users as confirmed in the register.
  • Right to Correct Your DataUsers who identify errors in the AI-generated transcriptions may be able to flag or request corrections through Library and Archives Canada or the partner platforms (Ancestry, FamilySearch). The original census images are available for comparison to support correction requests.

Risks and safeguards

  • Reputational harmAI transcription errors in handwriting recognition may produce incorrect names or personal details in the public index, potentially misidentifying individuals or distorting historical family records.Safeguard: the index is flagged as AI-generated, AI use is disclosed to users, and the source census images remain accessible so users can verify transcriptions against originals.