Table 1.

Description of data items included, with data quality completeness of linked dispensed prescriptions cancer registry data, for patients diagnosed with malignant cancer (excluding non-melanoma skin cancer) after 1994 with a dispensed prescription record during April to July 2015 (n=1 680 764 patients and 33 669 294 prescription items)

Data item	Description	Completeness* (%)
Pseudonymised patient identifier	Code derived from patient NHS no and DOB
Month	The month for which the claim for dispensed items has been submitted to NHSBSA.	100
Prescribed date	The date on which the prescription item was prescribed and submitted to EPS by the prescriber organisation. Note: only available for EPS messages	27
Prescribers postal code	The postal code of the prescribing practice, as held by the NHSBSA master database and the NHS Digital Organisation Data Service (ODS). It is in text and numerical format as per standard postal codes.	27
Primary care organisation (PCO) code	The code allocated by ODS to the prescriber’s Clinical Commissioning Group or other PCO. It is a five-digit code containing numbers and letters.	99.7
PCO name		100
Practice code	The code of the general practice that carried out the prescribing, or other cost centre which is coded as a general practice in the NHSBSA master database. The code is allocated by NHSBSA. It is a six-digit code containing numbers and letters.	>99.9
Practice name		>99.9
Net ingredient cost	This is the cost (in pence) of the dispensed item calculated from the reimbursement price held on the NHSBSA master database. The reimbursement price is the basic price for the quantity supplied of those drugs, appliances and chemical reagents as listed in parts VIII or IX of the Drug Tariff. For a drug not listed in part VIII, the price is normally determined by the list price published by the manufacturer, wholesaler or supplier of the pack size used for a prescription of that quantity.	100
Prescribed quantity	A specific quantity prescribed of a drug or appliance. Note: only available for EPS messages	100
No of items	This shows the no of times a product appears on a prescription form or EPS message.	100
Unit of measure	A description of the physical entity that can be handled, that is, tablet, ampoule, phial, mL. The unit of measure is held by the Dictionary of Medicines and Devices (dm+d) where this is appropriate to the product.	100
Pay quantity	The quantity of a drug or appliance which the NHSBSA has reimbursed. Where the product is packed in a special container, the quantity may be expressed as the no of special containers dispensed.	100
Drug presentation paid	A description of the product reimbursed as held by the dm+d. Where this is an actual product, the description includes the name of the proprietary or generic item, along with the supplier/manufacturer name. Where the product is a prescribable generic, the description of the generic product without supplier or trade name information is given. Note: on many occasions this will be the same as that prescribed.	100
BNF code	The NHSBSA database allocates BNF codes to drugs and medical devices: these codes are structured according to a series of hierarchical levels. Each level provides information about either the therapeutic use or pharmacological group of the drug or appliance. The structured coding is based on the BNF, with drug and appliance entries being arranged according to the BNF chapters, plus additional pseudo-chapters created by the NHSBSA.	>99.9
Patient age	The age of the patient, in years, on the date the item was prescribed.	82
Exemption category	The exemption category declared by the patient on the prescription form or included in the EPS message. Where the age/DOB is computer generated on the prescription, this is used for age exemption purposes.
	The exemption category declared by the patient on the prescription form (note that this can be completed in prescription items from EPS messages).	99
	The exemption category included in the EPS message.	27
	Indicator whether exemption category was declared by the patient on the prescription form or included in the EPS message.	100

*The number of dispensed prescription items with a known value as a percentage of all dispensed prescription items (both FP10 and EPS).

BNF, British National Formulary; DOB, date of birth; EPS, Electronic Prescribing Service; NHSBSA, NHS Business Services Authority; NHS, National Health Service.