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APC Data Consistency


The Admitted Patient Care (APC) Data Consistency Standards have been in place since 1st April 2009. These were mandated in order to ensure effective monitoring of performance in terms of data consistency, one of the key components of data quality as described in About Data Quality. These standards comprise a list of indicators and associated targets by which compliance is monitored on a monthly basis using the APC Data Consistency reports.

This document describes the background, purpose and logic behind each of these standards in detail. The associated Ministerial Letter was issued by Welsh Government to notify the service of actions required to implement the necessary changes.

The validation rules* applied to the data items within the APC data set are explained in detail on the NHS Wales Data Switching Service* webpages.

Any changes to these standards are described on the Change History page.


Some of the consistency checks refer to the sex of the patient.  The metadata used for these checks is shown here.

The sex flags are maintained and distributed by the NHS Classifications Service in the ICD-10/OPCS-4 metadata files.  These flags are reviewed and updated annually by HSCIC (Health and Social Care Information Centre).


* Currently accessible to NHS Wales Users Only