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

  • 293 Million records
  • 17.8 Million people
  • 16 average links per person

NSW NSW data that contributes to the CHeReL Master Linkage Key

Admitted Patient Data Collection

Jul 2001 - Sep 2021
53,994,935 records

(updated quarterly)

Private hospitals until June 2020

 

Emergency Department Data Collection

Jan 2005 - Sep 2021
41,228,407 records

(updated quarterly)

 

 

 

Perinatal Data Collection

Jan 1994 - Dec 2020
2,489,268 records

45 and Up Study

Updated Jan 2018
266,550 records

Central Cancer Registry

Jan 1972 - Dec 2018
1,393,065 records

RBDM death registrations

Jan 1985 - Sep 2021
1,722,144 records

(updated quarterly)

RBDM birth registrations

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

Notifiable Conditions Information Management System

Jan 1993 - Dec 2019
1,490,009 records

Perinatal Death Review Database

Jan 2000 - Dec 2016
12,626 records

Cause of Death Unit Record File

Jan 1985 - Dec 2019
1,633,109 records

Mental Health Ambulatory Data Collection

Jan 2001 - Jun 2021
51,428,037 records

NSW ANZDATA

1963 - 2020
328,605 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 - Sep 2021
12,224,089 records

BreastScreen NSW

Jan 1998 - Dec 2020
7,444,894 records

Non-admitted Patient Data Collection

Jul 2015 - Sep 2021
90,866,776 records

ACT ACT data that contributes to the CHeReL Master Linkage Key

Admitted Patient Collection

Jul 2004 - Jun 2021
1,699,559 records

Cancer Registry

Jan 1994 - Dec 2018
38,690 records

Emergency Department Data Collection

Jul 2005 - Jun 2021
1,979,523 records

ACT Perinatal Data Collection

Jan 1997 - Dec 2019
90,225 records

Notifiable Diseases Management System

Jan 2000 - June 2020
80,399 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.