1. Statistics reported in this publication are based on a national survey of the housing stock, the only one of its kind in Scotland, which is part of the Scottish Household Survey ( SHS). Until 2012 it was carried out as a stand-alone survey under the name Scottish House Condition Survey ( SHCS). Following the review of the large-scale Scottish population surveys, the SHCS was incorporated within the SHS and became one of its modules. We continue to report the results from this module of the SHS under the name Scottish House Condition Survey.
2. The SHCS consists of an interview with householders and a physical inspection of the dwelling they occupy to provide a picture of Scotland's occupied housing stock. It covers all types of households and dwellings across the country - whether owned or rented, flats or houses. The physical data about the dwelling is recorded by surveyors trained to collect detailed information on housing characteristics. This is combined with information about the household collected through a face to face interview with the householder. The interview covers a range of topics such as household characteristics, tenure, neighbourhood satisfaction, dwelling satisfaction, health status, income, etc. The result is a powerful data set for examining the condition and characteristics of the dwellings alongside the views and experience of the people living in those dwellings.
3. This is the twelfth 'Key Findings' report since the SHCS changed to a continuous format in 2003 and the fourth since it was integrated within the SHS. Details on the methodology and design of the survey are provided in the SHS Technical Report due to be published shortly on the Scottish Government website  . The incorporation of the SHCS within the SHS introduced some discontinuities in the methodology of the survey and may be contributing to some observed change over time.
4. The new survey design resulted in a small reduction of the sample where a physical inspection of the dwellings was undertaken. In some cases this limits the level of detail we can provide compared to previous years. In 2015 there were 2,754 surveyed properties compared to 3,219 in 2011. Statistics published in this report are based on fieldwork undertaken during 2015. A small proportion (10%) of the household interviews took place in the first quarter of 2016.
5. In 2009, the SHCS was designated as a National Statistics product by the UK Statistics Authority ( UKSA). This demonstrates that the SHCS statistics are accurate, trustworthy and compliant with the high standards required of National Statistics.
6. The analysis of the energy performance of the housing stock reported in this publication is based on the Building Research Establishment Domestic Energy Model ( BREDEM) 2012  first adopted for the 2013 SHCS Key Findings Report published in December 2014  . The methodological change that this involved affected comparability with previously published statistics on energy efficiency, fuel poverty and carbon emissions from housing. Details of this impact and revised estimates for the preceding 3 years were published in the 2013 SHCS Key Findings report and the accompanying Methodology Notes , .
7. An update to the BREDEM 2012 methodology, version 1.1, was published in January 2015  . This updated version was used for our 2014 Key Findings report. This introduced further discontinuities in the estimates of energy efficiency, emissions and fuel poverty, details of which are provided in the 2014 main report and the accompanying Methodology Notes  . There have been no further changes to the energy modeling methodology and the current 2015 Key Findings report is based on the same version of BREDEM.
8. The 2014 Key Findings report also introduced some improvements to the method for determining the cost of the energy required to maintain an appropriate standard of heating and other energy use which underpins the fuel poverty estimates. This involved allowing for Warm Home Discount and sourcing fuel prices which better reflect the experience of Scottish households. Details on the nature of the changes and their impact are provided in the 2014 Methodology Notes publication  . The current report continues to use this improved method for setting the cost of the domestic energy requirement.
9. There are no significant methodological changes in this year's report in comparison to the previous publication. We always seek to improve and keep up to date our methods and processes and there may be small changes to elements of data processing which do not impact significantly on the results. In such cases details are provided in the respective technical sections.
10. The remainder of this report covers the following topics:
- Key Attributes of the Scottish Housing Stock: this chapter describes key characteristics of the housing stock such as the dwellings' type and age of construction, their location in relation to the gas grid, and the characteristics of the households that occupy them.
- Energy Efficiency: this chapter presents an analysis of the energy efficiency of the housing stock including presence and level of insulation.
- Fuel Poverty: this chapter presents an analysis of the number and characteristics of households in fuel poverty and extreme fuel poverty. It also examines the key drivers of fuel poverty and how they have changed over time.
- Perceptions and Experiences examines householders' reports of their experience and satisfaction with heating and the extent to which they monitor their use of energy.
- Housing Conditions: this part of the report provides information on the number of dwellings in compliance with the tolerable standard and the Scottish Housing Quality Standard ( SHQS). It also covers the presence of dampness, condensation and disrepair as well as some indicators of overcrowding and under-occupation.
- Technical Notes, the final chapter in the report, provides information about the content of the survey and the definition of some of the key concepts used. Discussion on the statistical reliability of the estimates is also included.