skip to main content
  1. Home
  2. About our data and reports
  3. Methods
  4. Inflow, Outflow and turnover calculation

Inflow, Outflow and turnover calculation

The sections below explain the inflow, outflow and turnover calculations applied to the NHS Scotland workforce, Dentists and General Practitioner workforce. These calculations require individual-level data so that we can decompose, or break down, the data to estimate annual flows, for example, the number of people joining (or inflow) or leaving (or outflow) the workforce. Whilst the underlying data for these three groups are different, the methodology is the same.

More detailed inflow and outflow measures have been released for the first time as Official Workforce Statistics from June 2025. These calculations disaggregate the flows, and the types of flow differ between the NHS Scotland workforce, Dentists and General Practitioners groups. This is in part due to the data available. For example, access to training data for Dentists and General Practitioners mean we can identify the inflow from trainees.

Inflow, outflow and turnover calculations

We calculate the inflow (or number of joiners), outflow (or number of leavers), and turnover for the year ending 31 March year using the employment data.

  • Outflow is the number of staff who were employed at 31 March year n-1 and not employed at 31 March year n.
  • Inflow is the number of staff who are employed at 31 March year n and were not employed at 31 March year n-1.
  • Turnover is the outflow for the year ending 31 March year n, divided by staff employed at 31 March year n-1, and multiplied by 100.

For the NHS Scotland workforce, a staff member is identified in the employment data (SWISS) using a unique National Insurance Number.

For the dental workforce, General Dental Practitioners (GDPs) are identified by their General Dental Council (GDC) number in the MIDAS data source. GDPs includes a dentist who has completed Dental Vocational Training (DVT) and is working in the General Dental Service (GDS) and the Public Dental Service (PDS). General Practitioners (GP) are identified using their General Medical Council (GMC) number in the NPCCD data source. This will include any trained GP working in primary care at the census point (even if they are paid by a NHS Board).

We exclude Vocational Dental Practitioners, and GP trainees (Performer Registrars) from these calculations to avoid distortion caused by rotation of training placements.

The NHS Scotland workforce Official Statistics publication dashboard presents the inflow, outflow and turnover calculations for the NHS Scotland workforce (Turnover tab), Dentists (Dentists tab) and General Practitioners (General Practitioners tab). For NHS Scotland workforce, headcount or whole time equivalent estimates are available by occupation (Job Family, Sub Job Family and Band or Specialty and Grade), and contract type. For GDPs, estimates are available in headcount only by NHS Board and sex. Headcount estimates by NHS Board are available for GPs.

Detailed Turnover

NHS Scotland

One way to assess the mobility of the NHS Scotland workforce is to calculate the inflows and outflows within and out with NHS Scotland. To do this we disaggregate the inflow and outflows into three, mutually exclusive, sub-flows. These calculations are in headcount only.

Inflows for the year ending 31 March year n are defined as:

  1. Joined NHS Scotland: The number of staff who are employed in NHS Scotland workforce at 31 March year n and were not employed in NHS Scotland workforce at 31 March year n-1.
  2. Joining from another Board: The number of staff who are employed in NHS Board b at 31 March year n, and were not employed in NHS Board b, but were employed elsewhere in NHS Scotland, at 31 March year n-1. This works by using the NHS Board filter to select one or more boards (or regions). The charts will then show the number of people who joined the selected NHS Board(s) in each year ending 31 March from the NHS Boards that are not selected.
  3. Joining job from another within Board: The number of staff who are employed in NHS Board, b, and occupation, o, at 31 March year n, and were employed in NHS Board, b, but not in occupation, o, at 31 March year n-1. An occupation is selected using the Job family, Band/Grade group and / or Contract Type filters. If looking at Scotland level, the chart will show the number of people who have joined this occupation group from other occupations within NHS Scotland in each year ending 31 March. If the user is looking at a Board level, the chart will show the number of people who have joined this occupation group from other occupations in the selected NHS Board in each year ending 31 March.

Similarly, the outflows for the year ending 31 March year n are defined as:

  1. Left NHS Scotland: The number of staff who are employed in NHS Scotland workforce at 31 March year n-1 and were not employed in NHS Scotland workforce at 31 March year n.
  2. Leaving to another Board: The number of staff who are employed in NHS Board b at 31 March year n-1, and were not employed in NHS Board b, but were employed elsewhere in NHS Scotland, at 31 March year n. This works by using the NHS Board filter to select one or more boards (or regions). The charts will then show the number of people who have left the selected NHS Board(s) in each year ending 31 March.
  3. Leaving job for another within Board: The number of staff who are employed in NHS Board, b, and occupation, o, at 31 March year n-1, and were employed in NHS Board b, but not in occupation, o, at 31 March year n. An occupation is selected using the Job family, Band/Grade group and / or Contract Type filters. If looking at Scotland level, the chart will show the number of people who have left this occupation group for other occupations within NHS Scotland in each year ending 31 March. If the user is looking at a Board level, the chart will show the number of people who have left this occupation group for other occupations in the selected NHS Board in each year ending 31 March.

The counts for this are calculated contextually, e.g. joiners and leavers will update depending on the exact group you have filtered for and do not total up. If you are looking at a Scotland level it will not total all the moves that have occurred within Scotland, only the moves that have gone in and out of Scotland as a whole.

Example 1 An individual employed in NHS Tayside on 31st March 2024 and is then employed in NHS Grampian on 31st March 2024.

  • If the user is looking at all Boards (e.g no Board filter applied), then this individual would not appear as a joiner or a leaver.
  • If the user has filtered to the North region (selected Highland, Grampian, Orkney, Tayside, Western Isles, and Shetland in the Board filter), then this individual would not appear as a joiner or a leaver.
  • If the user has filtered to NHS Tayside in the Board filter, then the individual would be classed as Leaving to another Board. Similarly, if the user has filtered to NHS Grampian, then the individual would be classed as Joining from another Board.

Example 2 An individual is employed in NHS Lanarkshire under the Administrative services job family at 31st March 2024 and is then employed in NHS Lanarkshire under the Nursing & Midwifery job family at 31st March 2025.

  • If the user is looking at all Boards (e.g no Board filter applied) and all jobs (e.g no Job family, Band/Grade group or Contract Type filters applied), then this individual would not appear as a joiner or a leaver.
  • If the user has filtered to NHS Lanarkshire in the Board filter, then this individual would not appear as a joiner of a leaver.
  • If the user has selected the Administrative services in the Job Family filter, (either at a Scotland level or at NHS Lanarkshire) they would appear as a leaver to other job. Similarly, if the user has selected Nursing & midwifery in the Job Family filter, they would appear as a joiner from another job.

Dental and General Practitioners

We provide different sub-flows for GDPs and GPs. The is mostly since we are dealing with specific workforce groups for which we have access to training and education data that we can link with employment.

GDPs includes a dentist who has their DVT and is working in the GDS or PDS.

GPs include any trained GP working in primary care at the census point (even if they are paid by a NHS Board).

The inflow into the GDP or GP workforce in the year ending 31 March year n can be split into three sub-flows:

  1. Inflow from trainee: The number of GDPs or GPs who are first employed in the GDP or GP workforce at 31 March year n and were previously observed as a VDP or GP trainee.
  2. Inflow from returners: measures the number of GDPs or GPs who have left the workforce and returned. More specifically, for dentists, it is the number of GDPs who were not employed in the GDP workforce at the previous time, 31 March year n-1, but are employed at 31 March year n, and have previous employment as a GDP, n < n-1. Similarly, for GPs it is the number of GPs who were not employed in as a GP at the previous time, 31 March year n-1, but are employed at 31 March year n, and have previous GP employment, n < n-1
  3. Inflow from other sources: The number of GDPs or GPs who were first employed in the GDP or GP workforce at 31 March year n and had previously never been observed in the GDP or GP workforce (including as a VDP or GP trainee).

Both the GDP and GP data are from 31st of March 2009. Therefore, if a GDP was a VDP, or a GP a trainee, before that time, and joined the workforce, or they were a GDP or GP and returned to the workforce, they would be included in the inflow from other sources sub-flow.

The outflow from the GDP or GP workforce in the year ending 31 March year n can be split into three sub-flows:

  1. Left Scotland: The number of GDP or GPs who were employed in the GDP or GP workforce at 31 March year n-1 but are not employed in the GDP or GP workforce in Scotland at 31 March year n,
  2. Left Board: The number of GDP or GPs who are employed in the GDP or GP workforce in NHS Board, b, at 31 March year n-1, and were not employed in the same workforce in NHS Board b, but were employed in Scotland, at 31 March year n. This works by using the NHS Board filter to select one or more boards (or regions). The charts will then show the number of people who have left the selected NHS Board(s) in each year ending 31 March.
  3. Left Other: The number of GDPs who are employed in the GDS or PDS in NHS Board, b, at 31 March year n-1, and were employed in NHS Board b, but as a Hospital dentist at 31 March year n. This is not relevant for GPs.

Data quality

In a small number of cases the inflow and outflow will be caused by administrative updates to correct an error in a National Insurance number, GDC Number or GMC Number.

For VDPs, there are some missing GDC numbers within the Vocational Dental practitioner data extracted from TPM. If these VDPs transition into the GDS or PDS workforce they will be included in the “Other inflow”. The proportion of missing GDC number in the VDPs each year is small.