Scottish Vacant and Derelict Land Survey 2022

Annex: Data Quality and Processing

A.1. Data Quality

Details of the quality assurance checks undertaken on survey returns have been published on our website. View details of the Scottish Vacant and Derelict Land Survey quality assurance checks

A.2 Planning Authority response rate

The overall data quality for a particular year will depend on how many planning authorities have updated their survey for that year. If a planning authority does not update their data then data for the previous year is rolled forward. This will provide a reasonable estimate but will not take account of any changes in the latest year.

Annex Table 5 in the supporting file of tables records planning authority annual participation in the survey. Response rates should be borne in mind when using and interpreting the figures for authorities, including any time series and Scotland totals.

A.3 Removal and Addition of Sites

The means by which new sites are detected are largely centred on the expert knowledge of planning authority planning officers supported by the SVDLS guidelines which clearly state the definitions for the recording of derelict and urban vacant land. Sometimes a site or part of a site will be changed in such a way that it no longer meets the criteria for inclusion in the survey. Statistics on these sites removed for definitional reasons are reported in Annex Table 4 in the supporting file. Download the Scottish Vacant and Derelict Land Survey guidance for authorities (PDF).

A.4 Changes in Historic Data, 2016-2022

Revisions are carried out to improve the statistics supplied in the previous years. These are only carried out for up to six prior years. This is done to allow for improved time series analysis. Sites that planning authorities indicated had become derelict or vacant in previous years were added. Sites identified by the planning authority as having been re-used earlier or incorrectly included in the survey were removed. Increased use of GIS tools has resulted in more accurate mapping of sites over time. The revised data for 2016 to 2022 is used throughout the tables and time series analysis of this bulletin.

The SVDLS has been running continuously since 1993. Historical data on the amount of derelict and urban vacant land in Scotland for the years 2000 to 2015 is given in Annex Table 1 of the supporting file. These statistics are not revised and care should be taken when comparing 2000-2015 data in Annex Table 1 to the data shown in this publication.

A.5 Land area eligible

Local authorities are asked to note all derelict land for the survey but to limit recording vacant land to land within settlements as defined in their latest council approved local plan.

A.6 Coverage of Settlements

Local authorities were asked to survey for vacant land within all settlements defined in their latest council approved local plans. However, due to resource constraints some local authorities (particularly those covering large rural areas), were unable to do a full survey of every settlement for vacant land. All returned surveys covered every settlement with a population of 2,000 or more. To ensure consistency, the statistics presented on vacant land throughout this bulletin refer only to land located within settlements that have a population of at least 2,000 (according to the local plan). Some local authorities also undertook either a full or partial survey for vacant land in settlements of under 2,000 in population - these are reported separately from the rest of the bulletin in Annex Table 2 of the supporting file.

A.7 Estimate of the proportion of local authority population living within a defined distance of a Derelict Site

Tables 9 and 10 in the publication show estimates by local authority of the percentage of their population living within various distances of derelict land. For Table 9 a circular buffer zone based on the area of each derelict site was drawn around the grid co-ordinate points supplied for that site. This gives an estimated boundary for each site therefore data should be treated with care as actual site boundaries are not being used. Table 10 used the same estimated site boundaries and also estimated the proportion of local authority population living in close proximity to land that has been derelict prior 2001. In addition to derelict sites which were identified as being derelict prior to 2001 the analysis also included sites where the length of time derelict is unknown but where the first site inspection occurred prior 2001.

To measure the proportion of each local authority population that lives within a certain distance of derelict land, a national data set was constructed that estimated the population of each property identified as likely to be residential in the latest National Records of Scotland (NRS) Address Register. Average household size figures were calculated by dividing NRS census (2011) population by census household counts at the Census Output Area (COA) level. All records in the Address Register that were identified as likely to be residential were assigned an estimated household size figure based on the average household size of the COA they fall within.

To ensure consistency with previously published population estimates, the latest available small-area estimates of population by NRS were used as a control factor on the calculated household size figures. For each property in the Address Register based dataset, the distance to the nearest estimated derelict site boundary was calculated, to highlight those properties within the defined distance of derelict land. Those properties' estimated populations were then aggregated up by data zone to give a proportion of each data zone's population (and hence each local authority's population) estimated to live within the defined distance of derelict land.

A.8 Deprivation Areas using Scottish Index of Multiple Deprivation (SIMD 2020)

Table 11 shows the amount of derelict and urban vacant land located within Scotland's 15% most deprived data zones. Those data zones are identified using the 2020 Scottish Index of Multiple Deprivation (SIMD). The SIMD 2020 identifies small area concentrations of multiple deprivation across all of Scotland. Sites in the SVDLS are identified as being located within Scotland's most deprived areas if their grid co-ordinate point (i.e. the centre of the site) falls within a 15% most deprived data zone. Care should be taken with this data as there are instances of sites crossing data zone boundaries, hence part of the site may be in a 15% most deprived data zone, whilst the other part could be outwith. Further information on the SIMD 2020 project can be found on the Scottish Government's web page at: Visit the Scottish Index of Multiple Deprivation webpage.