Fig. 1

Step-by-step overview of linkage procedure and data coding system to enable data linkage for the HISlink 2018, Belgium

NRN: National Register Number; Statbel: the Belgian statistical office; RN: Random Number; SPOC NIC: Single Point of Contact National InterMutualistic College; TTP CBSS: Trusted Third Party Crossroads Bank for Social Security; IMA DWH: InterMutualist Agency Data Warehouse; TTP eHealth: Trusted Third Party eHealth; SCRA: Small Cells Risk Analysis; C1/C2: coding 1/2; Cproject: project specific coding

Explanatory note: the link involved the following steps, Fig. 1

1. Statbel selects the NRN of BHIS participants and transmits this selection of NRN to the NIC (1.1) and the selection of NRN with an internal RN (Random Number) specific to this project to the TTP eHealth (1.2). The NIC Security Advisor transmits an NRN/C1-encoded list of persons to the TTP eHealth, with C1 encrypted (1.3)

2. The TTP eHealth sends via the secure eHbox Cproject/RN to the TTP CBSS (2.1). The TTP eHealth sends via the Cproject/C1 secure eHbox to the TTP VI (2.2). Statbel transmits BHIS data on an NR basis to the TTP VI (CBSS° (2.3)

3. On the basis of a second coding (C1 → C2), the data are selected from the IMA DWH (3)

4. The data is sent back on a C2 basis to the TTP CBSS (4)

5. TTP CBSS replaces C2 with Cproject and also converts the received data into Cproject. These are transmitted to the IMA DWH (5)

6. A small cell risk analysis (SCRA) is carried out by the IMA (6)

7. The data sets are made available to Sciensano researchers (Cproject) (7)