Master Linkage Key (MLK)

The Master Linkage Key is a system of continuously updated links within and between core health-related datasets in NSW and the ACT. Both person and family-based extractions are available, as are tailored linkage services using additional datasets.

Quality assurance checks are regularly carried out on the Master Linkage Key.  For more information on our quality checks and procedures see the Quality Assurance page. 

CHeReL Master Linkage Key

  • 315 Million records
  • 18 Million people
  • 17 average links per person

NSW NSW data that contributes to the CHeReL Master Linkage Key

Admitted Patient Data Collection

Jul 2001 - Mar 2022
56,367,528 records

(updated quarterly)

Private hospitals until June 2021

 

Emergency Department Data Collection

Jan 2005 - Mar 2022
42,710,229 records

(updated quarterly)

 

 

 

Perinatal Data Collection

Jan 1994 - Dec 2020
2,489,268 records

45 and Up Study

Participants recruited 2008/2009
266,513 records

Central Cancer Registry

Jan 1972 - Dec 2019
1,448,212 records

RBDM death registrations

Jan 1985 - Mar 2022
1,751,133 records

(updated quarterly)

RBDM birth registrations

Jan 1994 - Dec 2020 (and 1990-1993)*
3,148,862 records

*identifiers for these records may not be complete

Notifiable Conditions Information Management System

Jan 1993 - Mar 2022
1,593,496 records

Perinatal Death Review Database

Jan 2000 - Dec 2020
14,127 records

NSW NCIMS-COVID Cases

Jan 2020 - Dec 2021
213,833 records

NSW ANZDATA

1963 - 2020
328,605 records

Mental Health Ambulatory Data Collection

Jan 2001 - Dec 2021
53,212,631 records

NSW Pap Test Registry

Jul 1996 - Jun 2017
15,075,884 records

Australian Early Development Census

2009,2012,2015,2018
391,732 records

NSW Ambulance

Jan 2005 - Mar 2022
12,667,625 records

BreastScreen NSW

Jan 1988 - Dec 2021
7,735,661 records

Non-admitted Patient Data Collection

Jul 2015 - Mar 2022
99,065,468 records

Cause of Death Unit Record File

Jan 1985 - Dec 2020
1,685,162 records

ACT ACT data that contributes to the CHeReL Master Linkage Key

Admitted Patient Collection

Jul 2004 - Jun 2021
1,699,559 records

Emergency Department Data Collection

Jul 2005 - Jun 2021
1,979,523 records

Cancer Registry

Jan 1994 - Dec 2019
41,115 records

ACT Perinatal Data Collection

Jan 1997 - Dec 2019
90,225 records

Notifiable Diseases Management System

Jan 2000 - June 2021
84,584 records

ACT BDM death registrations

Jan 1985 - Jun 2021
46,394 records

ACT BDM birth registrations

Jan 1997 - Dec 2020
135,321 records

Australian Early Development Census

2009,2012,2015,2018
20,510 records

ACT Kindergarten Health Check

2014, 2015, 2016
15,124 records

ACT ANZDATA

1963 - 2020
17,674 records

ACT Ambulance

2011 - 2020
373,750 records

Upcoming Upcoming data that contributes to the CHeReL Master Linkage Key

External Datasets

For information on other frequently-linked datasets outside the MLK, see the additional datasets page.