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From April 2024, data from the Waiting List Minimum Dataset (WLMDS) will be published alongside the monthly RTT data. This WLMDS release includes a national level timeseries (from Sep-21) and breakdowns by treatment function and by provider for data for the last week in the preceding month for new, open and completed RTT pathways. The % waiting for first attendance within 18 weeks is included in the national level timeseries from April 2023, when a field to collect first activity date was added to the collection, and is broken down by treatment function and by provider for data for the last week in the preceding month. 

From July 2025, WLMDS data is published split by demographic categories. The data is broken down by age, sex, ethnicity and deprivation (indices of multiple deprivation deciles). The data is management information and should be treated with caution, particularly at lower granularities where data quality may vary. Users of the data may wish to examine the figures alongside ONS population estimates to determine where variation is a result of population demographics.

Information from the WLMDS has previously been released on an ad hoc basis via the NHSE statistics pages as Supplementary Information.

Waiting List Minimum Data Set summary

WLMDS-Summary-to-29-Jun-2025 (XLSX, 292KB)

Waiting List Minimum Data Set breakdown by key patient demographics

Overview

Understanding patient demographics is an essential step in identifying and tackling health inequalities. The Elective Reform Plan included a commitment to publish waiting list information broken down by demographics to allow greater visibility of potential health inequalities. This enables local health services to understand the demographics of patients on their waiting list to better tailor services to their needs.

The data consists of four files: ·

Excel file giving an overview of key numbers at England, region, ICB and provider level
WLMDS-Demographics-Summary-to-29-June-2025-v1

CSV file providing separate age, sex, ethnicity and indices of multiple deprivation deciles (IMD) breakdowns by geography, down to provider level
WLMDS-Demographics-Geography-to-29-June-2025-v1

CSV file providing separate age, sex, ethnicity and IMD breakdowns by treatment function code (specialty) at England level
WLMDS-Demographics-Specialty-to-29-June-2025-v1

CSV file providing separate age and sex breakdowns by week ending date (from September 2021) at England level
WLMDS-Demographics-Timeseries-to-29-June-2025-v1

Due to the level of granularity in the data, there is potential for small numbers in the data that could be identifiable. To guard against this, the following rules have been applied, which are based on the suppression rules used for Hospital Episode Statistics (HES) publications:

1. Where the national total is between 1 and 7, subnational figures are masked (*)
2. Where the national total is >= 8, subnational figures between 1 and 7 are masked (*)
3. Remaining values are rounded to the nearest 5

Scope and background

The Waiting List Minimum Dataset (WLMDS) is a weekly data collection relating to demand, activity and waiting lists for elective care.

Providers of NHS services that fall within the scope of Referral to Treatment (RTT), such as acute trusts, specialist trusts and any other provider of consultant-led services for NHS patients (including independent sector providers) submit data weekly to NHS England.

Data in the WLMDS must be recorded in line with rules and definitions that are outlined in the RTT Rules Suite, published by the Department of Health and Social Care: https://www.gov.uk/government/publications/right-to-start-consultant-led-treatment-within-18-weeks. NHS England also publishes the RTT Recording and Reporting Guidance (and supporting Frequently Asked Questions document) which supports the RTT Rules Suite by providing further guidance on recording and reporting RTT waiting times: https://www.england.nhs.uk/statistics/statistical-work-areas/rtt-waiting-times/rtt-guidance.

Format of the data collection

The WLMDS RTT data collection template is in three sections:

• RTT open (incomplete) pathways
• RTT clock starts (new RTT periods)
• RTT clock stops (completed pathways)

Data quality

Provider organisations are responsible for ensuring that the data they submit is an accurate representation of RTT waiting and waited times, however, the WLMDS dataset is considered to be management information and is subject to less validation than the monthly official RTT statistics  (https://www.england.nhs.uk/statistics/statistical-work-areas/rtt-waiting-times/). There may be issues regarding the quality and completeness of the recorded WLMDS data which are not routinely reviewed centrally.

Providers began submitting data on a weekly basis in April 2021. Published time series include data from September 2021, allowing a period for bedding-in of data collection requirements.

Where providers are not able to submit before the weekly deadline, or discover an error after submission, they can submit a resubmission request. Published time series data includes resubmissions available at the time of extraction. However, no adjustments or estimations have been made for missing data. The time series includes a count of the total number of providers that have submitted data to give some indication of the data completeness.