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Publication, Part of

Dental Earnings and Expenses Estimates 2019/20

Current Chapter

Background Data Quality Statement


Background Data Quality Statement

Introduction

The Dental Earnings and Expenses Estimates, series of Official Statistics provides a detailed study of the self-employed earnings and expenses of primary care dentists (Providing-Performer/Principal and Associate dentists) who carried out some NHS/Health Service work in England, Wales, Northern Ireland and Scotland in the applicable financial year. Dentists performing only private dentistry are not included.

The earnings and expenses estimates are based on a sample from HM Revenue and Customs’ (HMRC’s) tax self-assessment database. All analyses are carried out by HMRC statisticians on an anonymised dataset and only aggregate non-disclosive information is supplied to NHS Digital for publication.

This publication is used as evidence in remuneration negotiations and by the Review Body for Doctors’ and Dentists’ Remuneration (DDRB). Their needs are identified and met by the Dental Working Group (DWG) which agrees the content and structure of this publication. DWG is a technical group with a UK wide remit and membership. The members of the DWG are shown in the Relevance section.


Data sources

The dental populations for the earning and expenses estimates were derived from data provided by:

  • NHS Business Services Authority (NHS BSA) Information Services for dentists in England and Wales
  • The Northern Ireland Health and Social Care Business Services Organisation (BSO) for dentists in Northern Ireland
  • NHS National Services Scotland: Information Services Division (ISD) for dentists in Scotland.

Where available, responses from the biennial Dental Working Patterns Survey of NHS primary care dentists are included in dentists’ records which are matched against HMRC’s Self Assessment tax database for the applicable year to estimate their earnings and expenses.

Earnings and expenses data come from self assessment tax returns held and analysed by HM Revenue and Customs statisticians.


Accuracy

The accuracy of the underlying data lies with the organisations providing the data. Missing or invalid data is removed from the datasets, and methods are continually being updated to improve data quality.

As the report is based on a sample, the findings are weighted to present results for the estimated dentist population as a whole. To do this, the population is stratified and appropriate weights are applied to minimise the effect of any bias in the composition of the sample.

Each country’s weighting factors are based on the strata (division of the population by age, gender etc.), and the same set of weights are applied throughout, for all results except the activity type analyses. Use of consistent weighting reduces complexity and potential risk of error. Standard errors are used where possible to assess the accuracy of the estimates. More detail is available in the methodology.

Because the results are based on samples with weighting applied, rather than the whole population, they are subject to sampling error and uncertainty. This is because using information from or about a sample of a population can never be as accurate as using the entire population.

Differences between groups and subgroups of dentists, or changes from one year to the next may not be statistically significant. Statistical significance is used in this report to illustrate the extent to which users can be confident that differences between compared results are not due to chance.

In addition, small dental populations for some subgroups mean that extreme values can have noticeable effects on the averages, and results in these instances may be subject to greater uncertainty.

Results shown in the Dental Earnings and Expenses Estimates reports are rounded to the nearest £100 to show that the results are not exact. Similarly, population estimates are rounded to the nearest 50. Percentage changes and ratios are calculated using unrounded figures.

Figures are estimates and summarise how dental earnings and expenses have changed over time. However, it is important to note that they include both NHS and private work, and both full-time and part-time dentists are included in the sample.

Report population figures stated in the report are estimated and should not be regarded as the definitive dental populations; they will not be the same as those population estimates published in other NHS Digital reports. This is due to some dentists being excluded from the population for Dental Earnings and Expenses Estimates for reasons listed in the methodology section.

All results received from HMRC are carefully checked before inclusion in the publication. In certain analyses, results are supressed for groups with a small sample size, due to the sensitivity of earnings and expenses information.

Any changes to the methodology or presentation of results are discussed by the DWG prior to implementation. In addition, at each stage the report was further validated and quality assured by NHS Digital analysts unconnected with authoring the report.


Relevance

Dental earnings and expenses estimates are primarily used as evidence to be presented to the Doctors' and Dentists' Review Body to make annual recommendations on remuneration for dentists.

This report has been agreed by the Dental Working Group (DWG), which is chaired by NHS Digital and includes representatives from:

  • Department of Health and Social Care
  • NHS England and NHS Improvement
  • The Welsh Government
  • The Department of Health, Northern Ireland
  • Scottish Government
  • NHS National Services Scotland: Information Services Division
  • The British Dental Association
  • The Secretariat for the Review Body on Doctors’ and Dentists’ Remuneration
  • The NHS Business Services Authority Information Services
  • HMRC: Knowledge, Analysis and Intelligence Division
  • The National Association of Specialist Dental Accountants and Lawyers (NASDAL)

Coherence and Comparability

When making comparisons with other similar reports or other countries within the report it should be borne in mind that:

  • different dental contracts are in place in these countries
  • there are slight differences in the methods used to produce the different country sections of the report

Further information can be found in the methodology

The results for Northern Ireland and Scotland are largely comparable over time, and the report draws comparisons with estimates from the previous year. Where changes in the dental population or variable definitions mean that comparisons should be made with caution, explanatory footnotes are provided.

Due to a change in methodology used to determine dental type, for dentists in England and Wales, figures in this publication are not comparable to previously published results. Please see the methodological change notice for further details. 


Timeliness and Punctuality

The estimates are based on the HMRC Self Assessment tax records of dentists and analysis can be undertaken only after the closing date of the Self Assessment period. Therefore, each report refers to the previous tax year which is the most recent year for which Self Assessment tax data are available. For example, the report released in 2021 relates to the 2019/20 financial year.

The report contains data for dentists with an accounting year end (AYE) during the fourth quarter of the financial year only (i.e. 1 January to 5 April). This period most closely matches that of the activity data provided by NHS BSA, BSO and ISD, and has been found to be representative of the entire financial year. The tax data cover income from all dental sources, including private dental practice.

There have been no issues in relation to punctuality in the production of this report.


Accessibility

All reports are accessible via the NHS Digital website and include supporting CSV and Time Series files and a web-based interactive report.


Performance Cost and Respondent Burden

The report is secondary use of the dental data provided by NHS BSA, BSO and ISD and therefore adds no burden to the NHS.

The HMRC data used within the analyses is also a secondary use of an existing administrative database (the Self Assessment tax database) and adds no additional burden to the dental industry.

The Dental Working Patterns Survey is a short biennial online survey of primary care NHS dentists. The survey takes approximately fifteen minutes and is the only source of this information. The primary purpose of the survey data is to produce a separate report, Dentists' Working Patterns, Motivation and Morale (formerly known as Dental Working Hours), and so use of the data in Dental Earnings and Expenses Estimates is a secondary use which adds no additional burden to the dental industry.


Confidentiality, Transparency and Security

All publications are subject to a standard NHS Digital risk assessment prior to issue. Disclosure control is implemented where judged necessary.

In order to maintain taxpayer confidentiality, HMRC suppressed the results for any analyses that would produce results for subgroups with low sample numbers and performed secondary suppression where required to ensure suppressed results cannot be calculated.

Data are held on secure, encrypted servers and transferred on secure file transfer systems or secure email. Data Sharing, Data Processing and Service Level Agreements exist between all parties involved in production of the report to ensure appropriate security levels are maintained.

The data contained in this publication are Official Statistics and comply with the UK Statistics Authority’s Code of Practice for Statistics.



Last edited: 22 August 2023 1:11 pm