Outpatient Dataset (OPD)

Data Providing Organisation:
NHS Wales’ Informatics Service (NWIS)

Data Providing Type:
Administrative (mandatory) data return



Attendance information for all NHS Wales hospital outpatient appointments.

Data Collection Method

The data are collected and coded at each hospital. Administrative information is collected from the central PAS (Patient Administrative System), such as specialty of care, appointment date and attendance status.

Data Highlights

This dataset contains all scheduled outpatient appointments, including those where the patient failed to attend.

Access Requirements

As a core SAIL dataset available in accordance with our standard Information Governance procedure.


Approx. 4,500,000 appointments per year

Data Level

Individual person

Data Years

2004 – Present

SAIL Schema