An applicant for immigration as a temporary or permanent resident is assigned a Unique Client Identifier (UCI), also known as a client identification number, when Immigration, Refugees and Citizenship Canada (IRCC) begins to process the application. It is distinct and different from the application number. A person will have the same client ID, but may have multiple application numbers - one for each application. Moreover, multiple client IDs can share the same application number, if they apply together for permanent residence on a single application. The UCI number is represented by the PERSON_UCID_CD variable in non-legacy data, and by the FOSS_CLIENT_ID variable in legacy data. Though it was expanded from 8 digits in the legacy period to 10 in the non-legacy period, the same numbering system was applied consistently through both time periods, so the same person is represented by the same number in either of these two variables. The UCI number is included in both permanent and temporary resident data in the repository. While IRCC includes hyphens in these numbers on their forms and documents, the hyphens are not included in the variables in PR and TRP datasets.