Immigration Detention in Hong Kong: Fostering transparency through data gathering and visualisation

Immigration Detention in Hong Kong: Fostering transparency through data gathering and visualisation


About the Project

Immigration Detention and Vulnerable Migrants in Hong Kong: Evaluating the System, Facilitating Reform” is a three-year research project at the Faculty of Law evaluating the immigration detention system in Hong Kong, particularly in relation to vulnerable migrants. The project began in July 2020 and will run through June 2023. This is the first detailed study of immigration detention in Hong Kong and will add significantly to comparative analysis of immigration detention in East Asia.

The project examines the functioning and effects of immigration detention law, policy and practice, with a focus on survivors of torture, victims of human trafficking, and low-income migrant workers. Based upon the findings, the research team will develop actionable, evidence-based guidelines for improving the system.

The inquiry is conducted through qualitative, socio-legal methods, including but not limited to: 1) analysis of primary documents such as government press releases, legislation, and policy documents, 2) extensive review of secondary academic literature and civil society reports, and 3) interviews with former detainees, civil society organisations, and other relevant stakeholders.

In addition to this, the project team has conducted extensive data gathering from the public domain; identifying, obtaining, processing, analyzing, and visualizing data to communicate patterns and findings.


About the Data

Publicly-available data on immigration detention in Hong Kong is extremely scarce. Considering that detention concerns persons deprived of their freedom, the lack of data is markedly concerning.

Centralized data on immigration detention in Hong Kong does not currently exist. Although the government has an open data portal, data on immigration detention does not feature there; instead, it is scattered across multiple government departments, sources, and file types, including but not limited to: Security Bureau documents, LegCo press releases, government submissions to the United Nations bodies, Immigration Department Annual Reports appendices, and more. To fill in the gaps within limited publicly available data, supplemental data has been obtained by the research team and others through meticulous requests made under the Code on Access to Information.

In the absence of centralized public data on immigration detention, the research team has established a data repository on the project website of the data that we have cleaned and compiled. The data page includes data visualizations for the general viewer and downloadable data for researchers and civil society members.

The research team has faced many challenges in obtaining even basic demographic data such as the number of detainees. These challenges include inconsistent measurement units, definitions, time units, and unformatted data. The limited data on detention has made comparative analysis, such as with prison institutions, increasingly relevant. Due to the scarcity and inconsistency of data, we clean and compile data across multiple sources for comparability across time periods and to ensure its accuracy.

Our hope is that the cleaned, compiled data and visualisations we have created will contribute to greater transparency about immigration detention in Hong Kong.

For more information on the project and the data page, please visit our project website at