Local Environmental Quality Survey of England

Survey Methodology 2014 - 2015 


The Local Environmental Quality Survey of England (LEQSE) is carried out annually by Keep Britain Tidy on behalf of the Department for Environment, Food and Rural Affairs (Defra).

The survey is not simply a measure of litter, it also includes six other indicators of cleanliness: detritus, weed growth, staining, graffiti, fly-posting and recent leaf and blossom fall. Taken together, these headline indicators provide a means of assigning a quantitative score to the local environmental quality of an area, based solely on the presence or absence of the indicators.

The main aim of the survey is to provide information on the overall cleanliness of the country. This can be used to inform strategy and is therefore crucial to ensure government, local authorities, land managers, businesses, Keep Britain Tidy and others have the information they need in order to improve local environmental quality.

Due to advances in technology and the creation of Lower Super Output Areas (LSOAs - boundary constructs created by the Office of National Statistics) this year’s survey sampling methodology was improved to better reflect land uses and allow the survey data to be linked to other data sets.

Historic data has been weighted to fit with the new methodology. This allows a comparison over time but means that data may be different to figures published in previous LEQSE reports.

Research into previous LEQSE sample sizes showed that a sample size of 7,200 sites across England would give a sufficiently representative picture. The number of sites surveyed within each region varied depending on the number of LSOAs present, and were split proportionately based on the total amount of LSOAs present in each region.

Five local authorities were chosen from each region, taking into consideration the different levels of deprivation within each local authority. Deprived communities often have lower levels of local environmental quality, so this sampling method ensures this is accounted for.

A total of forty five local authorities make up the national sample. These local authorities were then surveyed throughout the course of the survey year, spread evenly across the year by region.

The total number of LSOAs to be surveyed in each region was split proportionately across each of the five local authorities, based on the total number of LSOAs available in the five local authorities. Eight sites in each LSOA were surveyed; two sites at each of the four locations randomly selected using mapping technology.

To measure each indicator, a grading system is used. The grading system follows the same principles as the Code of Practice on Litter and Refuse, which identifies four grades of cleanliness: A, B, C and D. This survey uses these four grades, plus an additional three intermediate grades: B+, B- and C-. The order of the seven grades is shown in figure 1 below. The intermediate grades are not individually defined; put simply, if cleansing at any given site is not at an A standard, but is performing better than a B standard, it would be identified as a B+.

Local Environmental Quality (LEQ) grading system





None of the issues present

B +

Not formally defined


Predominantly free with some minor instances of the issue

B -

Not formally defined


Widespread with some accumulations of the issue

C -

Not formally defined


Heavily affected by the issue

Once the data is gathered, it undergoes rigorous quality assurance and then is analysed. To determine the local environmental quality of an area the data is analysed in two ways. The first method looks at the overall standard across the sites surveyed. This is done by converting the grades ‘A’ to ‘D’ to numeric equivalents and taking the mean average.

The second method calculates the percentage of sites below an acceptable standard. Sites below an acceptable standard are those classed as below a grade B,

In addition to average grade and percentage of sites below an acceptable standard, the survey also analyses the percentage of sites affected by individual littering issues or environmental crimes.

This analysis is not only done on England as a whole but on sub strata such as regions and land uses, ensuring a thorough picture of England, at all levels, is established.

In 2013/14, the way we collected the sample data was improved to better reflect the different land uses and enable us to link the data we collected to other data sets.

This revised sampling methodology has been retained for the 2014/15 survey and historic data has been weighted so that it fits with the new methodology, enabling direct comparisons to be made over time. 

The data has been investigated using statistical testing. Hypotheses test have been carried out to examine differences between groups of sites. A 95% level of confidence (adjusted to account for the series weights) is set as the critical point of statistical significance and where possible a 99% confidence level was used. Relationships between variables were examined using correlation analysis to assess the strength and direction of relationships.

'How Clean is England? interactive guide to LEQSE

Download the full 'How Clean is England?' 2014/15 LEQSE report

Download last year's 'How Clean is England?' 2013/14 LEQSE report


Land use definitions

Item definitions