16. Annex B: Methodology and source data
16.1 Notes about tables
To prevent repetition of notes beneath each table, generic notes are presented in this section. Specific points about individual tables are noted as they arise in the report.
Source data : Scottish Annual Business Statistics(SABS), Office for National Statistics, Marine Scotland. Fishing and Aquaculture figures are taken from analysis of Marine Scotland statistics rather than the SABS figures.
Table 32 summarises the main data sources for individual topics in this publication.
Table 32 : Source data for marine economic sectors
|Economic sector and SABS SIC Code
|Data sources – economic measures
|03.1: Fishing SABS data not used
|Marine Scotland Sea Fisheries statistics Seafish Fleet Economic Survey
|03.2: Aquaculture SABS data not used
|Marine Scotland Aquaculture Survey statistics: Shellfish Production Survey, and Fish Farm Production Survey Data Collection Framework (DCF) economic data
|09.1: Support activities for petroleum and natural gas extraction (extraction is not included in this publication)
|10.2: Processing and preserving of fish, crustaceans and molluscs
|SABS Seafish Processing Industry statistics – available but not used Number of Plants – Food Standards Agency
|30.1: Building of ships and boats & 33.15: Repair and maintenance of ships and boats
|42.91: Construction of water projects & 52.22: Service activities incidental to water transportation Marine tourism
|50.1: Sea and coastal passenger water transport 50.2: Sea and coastal freight water transport
|SABS Transport Scotland statistics
|77.34: Renting and leasing of water transport equipment
|SABS various SIC codes (see Annex A) supplemented by geographic filters to select businesses within 100m of the coast line
- Industry sector names are abbreviated for simpler presentation. Annex A contains the full SABS SIC title for the sector and the abbreviation used.
- Employment figures are head counts (not adjusted to Full Time Equivalents).
- GVA and turnover values are adjusted to 2016 prices
- Since 2011, support activities for oil and gas were extracted using the SIC code SIC 09.1: Support activities for petroleum and natural gas extraction. However, between 2008 and 2010 these figures were disclosive and so the wider code SIC 09 Mining support activities used to provide data. While there is little difference between the code values, it is important to note the change in coverage of the industry that is the largest contributor to the marine economy. The difference is minimal - see later in this section.
- Totals may not sum due to rounding and disclosure control.
16.2 Scottish Annual Business Survey
The majority of economic figures in this publication have been taken from the Scottish Annual Business Statistics (SABS) publication. This provides data on a number of economic variables across a range of sectors, based on data from the Annual Business Survey (ABS) conducted by the Office for National Statistics (ONS). The SABS statistics were produced under partnership procedures between ONS and the Scottish Government. These have resulted in an improvement in the quality of the underlying data and consistency in the figures used by ONS and SG.
SABS data is attributed according to business site address e.g. a shop or factory, so data for a large company can be split over more than a single site.
Rigorous checks are made to ensure that information relating to individual businesses are not disclosed, either directly or by deduction, in the figures released. In some cases this means that data cannot be presented at smaller geographies such as local authority areas.
To set the individual industry results in context, throughout this publication they have been considered in the context of the Scottish economy as a whole.
- The national GVA estimate was taken from the Quarterly National Accounts of Scotland.
- The total employment in Scotland was taken from ONS’ Business Register and Employment Survey (BRES), Table 3 - Employment by Region.
16.2.1 Sampling methodology
The ABS uses a register of businesses (the Inter Departmental Business Register (IDBR)) to produce an estimate of all businesses etc. that make up the population. The ABS sample is designed as a stratified random sample of UK businesses from the IDBR. The inquiry results are grossed up to the register population, so that they relate to all active UK businesses on the IDBR for the sectors covered.
Scottish Government also funds an enhanced ABS sample in Scotland, to improve the quality of Scottish figures. In 2016, around 2,600 extra firms in Scotland were sampled as a result of this boost, giving a total sample size in Scotland of around 8,200 firms.
Scottish Annual Business Statistics are published as soon as possible after the release of ONS’s regional results, which are due out each Summer. In 2018 the SABS figures for 2016 were released in 20th June, 18 months after the end of the relevant calendar year.
SABS publish information about sample sizes and error margins for the survey. https://www.gov.scot/Topics/Statistics/Browse/Business/SABS/QualityMeasures
16.2.2 Marine economic sectors
Marine economic sectors have been defined as those depending on the marine environment for their output, and where official statistics are available. The SABS data is used along with Marine Scotland’s own statistical publications to gauge each industry’s contribution to the Scottish economy. Where SABS is the sole source of data, the estimates are used directly. Where other sources are used the methodology is introduced in the relevant section of the report and explained more fully in this Methodology section.
Economic values have been adjusted to take inflation into account and are presented at 2016 prices. This means that they are directly comparable in a time series.
16.3 Geographic Distribution
The distribution of the whole marine economy was provided from SABS data. However, in this report economic statistics for fishing and aquaculture are not derived from SABS and so reconciliation was necessary for the economic values at local authority level. To achieve this, the fishing and aquaculture values were distributed to local authorities as far as possible and the residue, which could not be allocated, was assigned to an ‘unallocated’ category.
16.4 Price presentation
All values have been adjusted to 2016 prices using the GDP deflators https://www.gov.uk/government/collections/gdp-deflators-at-market-prices-and-money-gdp making it simpler to compare values across a time series.
16.5 Sea Fisheries Methodology
This provides a more reliable estimate of economic activity than the SABS figures, primarily because the landings data, which is the source data for ‘turnover’ covers the entire population rather than just a sample (as is the case with SABS).
The Marine Scotland statistics provide values for quantity and value of landings, employment in fishing and vessels registered in Scotland. Because Seafish figures are used for the economic values there is a slight discrepancy between the totals shown in this report and Marine Scotland Sea Fisheries Statistics.
The Seafish survey provides financial data, including total fishing income, that is used to estimate GVA for the Scottish fleet.
The methodology used in this publication varies slightly from that used in previous Marine Scotland topic sheets which estimated GVA using a five-year average of the GVA/revenue ratio derived from Seafish’s price data. It is intended that future topic sheets will use the methodology shown here.
Marine Scotland publishes Scottish Sea Fisheries Statistics as an annual National Statistics publication. The statistics provide a detailed overview of the quantity and value of landings of sea fish and shellfish by Scottish vessels, and landings into Scotland. The Marine Scotland data is a census of all landings by Scottish registered vessels. Information on the Scottish fishing fleet and the number of fishers on Scottish vessels is also presented. Scottish Sea Fisheries Statistics are obtained by data extractions from Scottish and UK databases from data supplied by skippers.
The Seafish Industry Authority carries out economic surveys of the UK fishing fleet, published as the Seafish Fleet Economic Performance Dataset (see above and footnote). This contains financial, economic and operation performance indicators for the period 2007-2017. The figures presented in this publication are an extract of economic performance data for all active vessels registered in Scotland.
The Seafish Fleet Economic Survey combines costs and earnings information from vessel accounts provided by vessel owners to the annual Seafish UK Fleet Survey, with official effort, landings and capacity data for Scottish registered vessels from Marine Scotland’s Sea Fisheries Statistics. In 2017, the Seafish survey collected 570 sets of financial accounts for the UK fleet (12% of the UK fleet).
16.5.1 Regional data
Seafish provided figures at local authority and Scottish Marine Region level so that a regional distribution of the turnover and GVA can be presented. Data was allocated to the geography based on the location of the registration port of the vessel. Reporting at this level introduces the possibility of disclosing commercially sensitive information. To prevent this happening, all other segmentation categories were aggregated (species type, fishing gear etc.) and outputs where five or fewer vessels were registered were restricted. This resulted in a small difference in total value and weight of landing totals between Seafish disaggregated totals and Scottish Sea Fisheries Statistics totals. The difference was reported in the tables as ‘Unallocated’ to the regions.
16.5.2 Seafish economic analysis methodology
Outputs from the Seafish Fleet Economic Survey were used in the fishing GVA estimation. Full details of the Seafish methodology are available in the Seafish Fleet Economic Survey, a summary is given here.
1. The UK fleet is stratified into fleet segments using MMO data on capacity, effort and landings for each vessel. For the data in this publication, only Scottish registered vessels were included and other segment criteria were suppressed.
2. Financial accounts were collected for each fleet segment.
3. Costs and earnings data from vessel accounts were allocated to fleet segments.
4. The cost structure of all vessels in each fleet segment is estimated by:
a) sum the individual cost and earnings items from vessel accounts within each segment sample.
b) calculate the proportion of the costs as % of fishing income e.g. sum of gear cost is 10% of sum of fishing income, sum of commission is 3% of sum of fishing income etc.
c) Fuel costs and crew costs are calculated differently from the other costs. For crew share, assign a minimum £100 per day, or the actual observed amount, whichever is the higher. For fuel costs, estimate fuel consumption in litres and combine with the average annual red diesel price (excluding duty).
d) Following calculation of fuel cost and crew share, apply the proportions from the other costs to the official declared fishing income for each vessel to calculate Gross Value Added, operating profit and net profit for each vessel.
5. UK fleet totals and fleet segment totals and averages are then calculated from the estimates produced for each vessel.
Where there are low sample sizes for a particular segment in a particular year previous years' estimates are taken into consideration.
16.6 Aquaculture methodology
16.6.1 Source data
The quantity and value of fin and shell fish produced on Scottish aquaculture sites is sourced from the Marine Scotland Aquaculture Surveys. The aquaculture surveys are census surveys, receiving a response from every active fish farm in Scotland.
The financial data is drawn from EU Data Collection Framework (DCF) data. The DCF sets out broad requirements for collecting social, economic and environmental data on aquaculture for the UK. The MMO acts as national correspondent for the data, and CEFAS collects the financial data for the UK. It is the CEFAS DCF survey data that provided the source financial data for estimating the aquaculture GVA for Scotland.
The sample numbers of DCF aquaculture data are not large. The table below shows sample sizes for Scotland over three years of DCF surveys as collected by CEFAS.
|Count of samples
16.6.2 Calculating GVA using DCF sample data and Marine Scotland survey data
1. The DCF sample data contains financial returns for UK aquaculture businesses, by year and by species type. For this analysis, DCF data for Scottish production of salmon, trout, and mussels is used to represent the aquaculture categories, salmon, other finfish, shellfish. See below.
|Trout and all finfish except salmon
2. Because the aquaculture survey is a census survey, the total production value can be assumed to estimate the value for Scotland. The DCF sample is scaled to Scotland level using the ratio of the DCF sample income to the Marine Scotland Aquaculture sample. i.e.
3. Multiply the DCF financial sample values by the sample weighting to estimate the values for Scotland.
4. For each species type, calculate, at the Scotland level, total outputs and total inputs.
5. Calculate the GVA to income ratio by
This GVA to income ratio can be used to estimate annual GVA where the output (value of the production in £) is known, e.g. for regional estimates. DCF data is available for 2013 to 2016 i.e. four years of data. A ratio is calculated for each of these years. To produce a longer time series, incorporating figures for before 2013, a mean GVA to income ratio was calculated and used to estimate the GVA from the known aquaculture turnover. This is noted in the tables.
Table 33 : GVA Ratios for aquaculture production
|GVA to income ratio
16.6.3 Comparisons with other data
SABS produces estimates for aquaculture GVA, turnover and employment. These have not been used because the aquaculture survey statistics are more complete than the ABS surveys. However, estimates for 2015 showed a considerable variance between SABS and estimates based on aquaculture data. This has been explored and the estimates in this publication seem to more accurately reflect the situation. In 2015, production was lower and costs higher due to biological problems such as sea lice and disease. This does not appear to have affected SABS survey estimates.
As with fishing estimates, aquaculture economic data has previously been reported in the Marine Scotland Economic Topic Sheet. The aquaculture method previously used a mean GVA to turnover estimate based on five years of SABS ratios. With the more specific data used for the estimates in this publication, individual years are estimated for 2014 to 2016. While the large change in GVA in 2015 did trigger investigation into potential preference for using a mean ratio, in fact the individual annual figures are felt to better demonstrate the industry performance.
However, specific years’ data was not available prior to 2013. To be able to estimate GVA for 2008 to 2012 a mean GVA : turnover ratio was calculated and applied to turnover in Table 24.
16.7 Oil & Gas
In this publication estimates for support activities related to oil and gas extraction are presented rather than the extraction itself. This retains consistency with National Accounts Statistics and ABS data where Oil & Gas extraction is normally allocated to a separate ‘Extra Regio’ category rather than allocated to a region within the UK.
ABS data relating to Oil & Gas extraction (SIC 6) is allocated to UK regions (including Scotland) according to the address at which the business is registered - onshore and offshore Oil & Gas extraction and activities are allocated in this way. GVA associated with off-shore activity, under UK regional accounts procedures, is normally allocated to a separate ‘Extra Regio’ category rather than allocated to a region within the UK.
The codes used to produce figures related to oil and gas production have changed from 2008 to 2016.
From 2008 to 2010, data was provided for SIC 09 Mining support service activities. This included both SIC 09.1: Support activities for petroleum and natural gas extraction and SIC 09.9: Support activities for other mining and quarrying. While ‘other mining and quarrying’ activities are not necessarily marine, they were included because publishing only SIC 09.1 at the Scotland level would have been disclosive.
Since 2011, only SIC 9.1 Support activities for petroleum and natural gas extraction have been included.
SIC 09.9 ‘other mining and quarrying’ is a small component of SIC 09. It is less than 0.02% of the employment, GVA or turnover of SIC 09.1 ‘Oil and gas services’ and so the series has been considered comparable and no break in the series is required. Footnotes to tables explain this and in the Oil and gas methodology section the differences are explored.
Table 34 below quantifies the difference between SIC 09.1 and SIC 09.9 to understand the impact of the change in categories. It is clear that SIC 09.9 is very small, and reported no employment in the SABS data presented, therefore having very little impact on the change in categories.
Table 34 : SIC Codes used for Support activities for Oil and Gas
|GVA - BaSIC Prices £m
|09.1: Support activities for petroleum and natural gas extraction
|09.9: Support activities for other mining quarrying
|SIC 09.9 as a percentage of SIC 09.1
Prices presented as baSIC values – not adjusted for inflation.
16.8 Fish Processing
Seafish carries out annual financial surveys of UK fish processors and a census of all UK fish processing businesses around every two years.
Their Seafood Processing Industry Report presents an overview and analysis of the UK seafood processing industry.
While the Seafish report has the advantage of providing sector specific economic data and does provide information on sea fish processing only (SABS provides all fish processing), it has not been used in this publication because:
Seafish economic data is presented for 2010 to 2014.
- Employment is collected in alternate years, 2010 to 2016
- Published employment data is provided as FTE for Scotland, i.e. inconsistent with the headcount figures used in the rest of this publication.
16.9 Water Transport Geographic Distribution Methodology
SABS provides an estimate of the GVA for Scotland for both freight and passenger water transport. These estimates were used as the sole source for economic reporting in this publication.
For the freight transport, DfT statistics provide a tables of tonnages of all freight traffic through UK major and minor ports. Using GIS, the Scottish ports were allocated to both Scottish Marine Regions (SMR) and Local Authorities which allowed an analysis of the geographical distribution of tonnage of freight. The total GVA for Scotland was apportioned according to SMRs by these percentages.
Passenger transport was not presented by specific ports and so no geographical breakdown was made.
16.10 Marine Tourism Methodology
Marine tourism and recreation has been defined as including “activities which involve travel away from one’s “habitual” place of residence, which have as their host or focus the marine environment and/or the coastal zone”. This is the definition used in the 2015 Scottish Marine Recreation and Tourism Survey.
In this Marine Economic Statistics report, the estimates extract tourism that was identified as ‘marine related’ from all tourism figures as presented in the Scottish Annual Business Statistics data. The approach taken treats all tourism businesses located in postcodes within 100 metres of the coastline as engaging in marine tourism and recreation, or dependent on the marine environment. This is the method that was used to produce the first estimates of Scottish marine tourism in the economic topic sheet released in 2017.
The list of SABS codes for relevant tourism and recreation business activities is provided in Annex A. It assumes that marine tourism and recreation businesses are located along the coast, and therefore may exclude relevant activities of tourism and recreation businesses that are located within postcodes that are more than 100 metres from the coastline. This approach also excludes loch, river, canal and other inland forms of water tourism, as these are not considered marine.
The 100 metre threshold was selected to minimise chances of including in the estimates activities of non-marine tourism and recreation businesses that are located along the coast, especially in urban coastal areas such as Aberdeen and Edinburgh.
A similar approach to estimating the economic contribution of marine tourism and recreation has been used by other EU member states such as Portugal and the Netherlands. The estimates in this report are therefore comparable with those produced by other countries. In addition, this methodology has been discussed with economists at the Oslo-Paris (OSPAR) Commission Socio-economic Working Group, and there is general agreement across member states on the principles of the approach.
In generating a geographic breakdown of the marine tourism sector, presenting the outputs by local authority was partially disclosive and Scottish Marine Regions (SMR) were selected as the lowest non-disclosive geography that could be used. While SMRs are developed strictly for information related to areas of sea within 12 nm of the coast, they were used in conjunction with the methodology described above to present both marine and land based tourism related to the sea.
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