All extracts were validated, back to source (raw) data to ensure that integrity had been maintained.
Some data used in this exercise are administrative and intended for only Secondary Uses, therefore the final patient list will be influenced by how data are recorded in supplier systems at point of care, and also how data are processed and transformed during data collection from data providers.
As a result, it is accepted that a small proportion of collected data may not be representative of the patient’s actual medical record.
To counter this, an extract of primary care data – specifically data derived from the seasonal influenza vaccination algorithm - was also used in the algorithm. Further, this was replaced by a weekly extract of primary care data to COVID-19 SPL. This signalled a significant shift from version 1.0 where primary care data was referenced during the assurance process but not applied in the algorithm.