The Referral to Treatment (RTT) weekly Patient Target List (PTL) Data Set contains unvalidated waiting times data for Welsh residents on an RTT pathway at a Welsh Local Health Board. The data set is a snapshot of the patients waiting on a Referral to Treatment (RTT) pathway as at the census/return period. The return includes patients that are on an open pathway and excludes any closed pathways. Private patients are excluded. If at any point along the Referral to Treatment (RTT) pathway a patient becomes an English resident, and their GP is an English GP then they will cease being reported as part of the Welsh Referral to Treatment (RTT) wait. RTT in Wales is limited to Welsh residents only. If a patient resides in England and has an English GP but is treated in Wales, they will be excluded from this dataset. Similarly, Welsh residents who are treated in England will also be excluded. Definitional guidance around Referral to Treatment (RTT) pathways is available on the Welsh Government’s website or by contacting hss.performance@gov.wales.