Applicants need to read the Non-Standard Linkage Service (NSLS) Application Form Guidance and complete and submit the following to the CPRD linkage mailbox (cprdlinkages@mhra.gov.uk):   

• The Non-Standard Linkage Service (NSLS) Application Form with any required supporting evidence, e.g. a data flow diagram 
• The New Client Request Form if the Applicant has not previously used CPRD data. 

CPRD will conduct an initial assessment of the NSLS Application Form (and the New Client Request Form if required) within one month, and inform the Applicant whether: 

• The New Client Request Form has been approved 
• The application form can be passed forward for to stage 1B for a detailed assessment.  

A non-refundable initial fee of £1,500 will be payable to CPRD for the processing of the application in Stage 1B and that CPRD will not commence stage 1B of the Non-Standard Linkage Service process until the full fee has been received by CPRD.   

CPRD will review the NSLS Application form to establish whether the linkage is viable based on a number of factors (i.e.  patient confidentiality, legal and technical feasibility, timescale, determining which approvals are required, etc.) and will then inform the Applicant whether the proposed linkage can be taken forward to the next stage. 

If the Applicant confirms that they wish to progress to Stage 2, a contract with CPRD will need to be signed, including a non-refundable service fee.  

Example 1: Individual patient-level linkage based on patient-level identifiers: 

CPRD will work with the applicant to: 

• Prepare, issue and sign a contract for the linkage process 
• Review information governance-related aspects of an ISAC application prior to submission  
• Apply for any other required approvals (e.g. HRA CAG or ODR), in collaboration with any other data controllers. 
• If required open and complete an NHS Digital Data Access Request Service (DARS) application, in collaboration with the applicant and any other data controllers. 

- CPRD will submit the DARS application to NHS Digital only once all other approvals are in place (e.g. ISAC, HRA CAG etc). 
- The NHS Digital DARS team will pre-review the DARS application and once this pre-review is complete, will present the application to the NHS Digital Independent Group Advising on the Release of Data (IGARD).  
- IGARD approval may require several resubmissions. CPRD will undertake one resubmission to IGARD as standard, further resubmissions may incur an additional service charges depending on the work needed.  

Once all approvals are in place, CPRD will: 

• Prepare a Data Sharing Agreement (DSA) with any third-party data controllers. 
• Prepare a Dataset Agreement with the applicant

Example 2: Non-standard linkage based on GP practice postcode (including release of the linked dataset) 

The process will be as above but potentially requiring fewer approvals (i.e. potentially excluding HRA CAG and the NHS Digital Data Access Request Service (DARS) application) but including the data linkage and release process below (stage 3).

Depending on Data Flows agreed between the applicant, any third-party data controllers and CPRD, the linkage will be undertaken by either NHS Digital or CPRD. For most non-standard linkages this process involves: 

• NHS Digital producing a bridging file to enable linkage of pseudonymised/de-identified datasets and sends this to CPRD 
• Any third-party data controllers provide CPRD with study relevant patient IDs and variables 
• CPRD then creates new linked dataset using the bridging file, CPRD data and the third-party data controllers provided data.  This includes re-pseudonymising all IDs to a study specific ID. 

CPRD, on behalf of the third-party data controllers, manages data releases to the applicant i.e. signing of the Dataset Agreement and secure transfer.