Cleanliness National Indicator (NI 195)


Using the Results

16.1

Introduction
16.1.1 The NI 195 survey may be used for several purposes:
  • to compare local cleanliness standards with national benchmarks, both overall and at the level of individual land uses;
  • where appropriate, to provide information on local performance for use in the context of a Local Area Agreement; and,
  • to provide management information that enables the authority to review the level of cleansing resources, priorities and cleansing strategies both overall, and in each of the standard land-uses.

16.2

What Are The National LEQSE Benchmarks?
16.2.1 The national benchmarks for litter, detritus, graffiti and flyposting are based on the results of the annual Local Environmental Quality Survey of England (LEQSE).
16.2.2 The current national benchmarks for NI 195 in terms of the % of sites graded below B (giving half-weighting to B – Grades) are set out in Table 16.2.1:
16.2.2 The current national benchmarks for NI 195 in terms of the % of sites graded below B (giving half-weighting to B – Grades) are set out in Table 16.2.1:

TABLE 16.2.1: 2007 / 2008 NI 195 National Benchmarks

LAND USE
Litter
Detritus
Graffiti
Flyposting

All Land Uses
11
21
4
1

Main Retail and Commercial
9
3
3
3

Other Retail and Commercial
14
12
7
1

High Obstruction Housing
9
24
1
0

Medium Obstruction Housing
5
19
2
1

Low Obstruction Housing
3
20
1
0

Industry and Warehousing
18
28
2
0

Main Roads
10
21
1
0

Rural Roads
12
32
1
0

Other Highways
20
35
16
0

Recreation Areas
8
16
5
0

16.3

What Is The NI 195 Target Set By Defra?
16.3.1 Defra will not be setting any national targets for NI 195 for litter, detritus, graffiti or flyposting.
16.3.2 However, where NI 195 is included in an authority’s Local Area Agreement, either as a National or a Local Indicator, targets may be set on a local basis.

16.4

Using The NI 195 Survey For Management Information
16.4.1 Every time a four-monthly survey is submitted to the online database, authorities will be able to generate a copy of a report containing tables and graphics, in the format of Figure 16.4.1.
16.4.2 At the end of the year, authorities should aggregate the results from their three four-monthly surveys, They will not have to make a formal return to Government. Defra will use the aggregated results as the authority’s return. (See Section 15.0)
16.4.3 For details on how to generate the report please see Section 14.0.
16.4.4

Figure 16.4.1 contains four elements:

- a NI 195 Results table showing the scores for litter, detritus, graffiti and flyposting both for all land uses overall, and for each individual land use;

- a ‘Gauge Chart’ graph showing overall standards for litter, detritus, graffiti and flyposting in a form that will be comparable to the results from the LEQSE report; and

- a ‘Line Graph’ indicating the Distribution of Grades – the percentage of transects assessed for each of the 7 Grades for litter, detritus, graffiti and flyposting;

- a set of ‘Audit Information’ aimed at assisting in the audit process.

16.4.5 NI 195 Results Table
This table shows the NI 195 Indicator results for litter, detritus, graffiti and flyposting. The figures will reflect the half-weighting given to B – grades.
16.4.6 Although NI 195 does not require a ‘combined’ score for litter and detritus, the table shows such a score in the third column. This is designed to offer some continuity and comparison with the former BVPI 199 format.
16.4.7 Gauge Chart
There are two Gauge Charts. The first shows the overall standard for each element of NI 195 for the local authority in terms of the Standard Quality Intervals (SQIs) used by the LEQSE, while the second shows the current national SQI benchmarks.
16.4.8 Each SQI represents an interval over which a reasonably observant person can see that a small, qualititative difference in standard has occurred for the local environmental element being examined.
Figure 16.4.1
16.4.1
16.4.9 A Standard Quality Interval is based on the average of all the grades assigned to all the sites covered in the NI 195 survey – not just those sites whose grade fall below a Grade B. It is possible for the same overall SQI to result from different combinations of grading assessments. (Note: the white square in the middle of SQIs in the ‘Poor’ category is designed to assist readers who may be colour-blind).
16.4.10 Distribution Of Grades
The distribution of grades will show, for each of the four elements of NI 195, the pattern of standards across the authority.
16.4.11 At national level, the proportion of sites which are assessed as Grade A (completely clean) for litter and detritus is relatively small, since there are at least small amounts of litter and detritus on most sites surveyed. The pattern for graffiti and flyposting is the opposite – on most sites, there are no traces of either.
16.4.12 Audit Information
  • the number of transects surveyed (a minimum of 300 overall, and a minimum of 30 in each land use present); and
  • the dates within which each of the four-monthly surveys should be carried out (for Tranche 1, 1st April to 31st July; for Tranche 2, 1st August to 30th November; and for Tranche 3, 1st December to 31st March).
16.4.13 If the colour code is green, then based on the information submitted to the database, these requirements have been met. If it is red, then it would appear that they have not been met. Just because the Audit information is green in does not necessarily mean that the data is completely accurate.
16.4.14 The second section ‘Local Authority Comments’ is to allow authorities to add background notes e.g. if there have been practical difficulties affecting the way the survey has been carried out. Please see section 13.0 for information on how to enter these notes.
16.5 Interpretation of NI 195 Results Table
16.5.1 Tables 16.5.1 and 16.5.2 show a possible pattern of results from a NI 195 Survey for litter and detritus. Table 16.5.1 shows the results in NI 195 format, based on giving half-weighting to B – grades. Table 16.5.2 shows the ‘raw’ data, in BVPI 199 format.
16.5.2 In Tables 16.5.1 and 16.5.2, the three highest scores for each element (two, in the case of flyposting) are highlighted in bold red.
16.5.3 In general terms, an authority should review its cleansing operations in the land uses where the figures are marked in bold red as a matter of priority, since they appear to present the greatest problems. These priorities may be modified, however, in the light of local circumstances.
16.5.4 In using the survey results for management purposes, authorities should always use the ‘raw’, unweighted data in BVPI 199 format. This is because, for operational purposes, managers will need to have estimates of the actual proportions of sites that fall below a Grade B. The use of weighted data might change the ranking of scores by land use (though it has not in the example shown).
Table 16.5.1 Local Authority NI 195 Data (Weighted)
LAND USE
Litter
Detritus
Graffiti
Flyposting
All Land Uses
15
19
8
3
Main Retail/Commercial
19
3
6
13
Other Retail/Commercial
9
2
15
7
High Obstruction Housing
23
30
2
2
Medium Obstruction Housing
9
18
2
0
Low Obstruction Housing
10
15
8
2
Industry/Warehousing
25
36
15
0
Main Roads
7
12
4
3
Rural Roads
18
27
3
0
Other Highways
23
22
19
2
Recreation Areas
9
39
6
1
Table 16.5.2 Local Authority NI 195 Data (BVPI 199 Format)
LAND USE
Litter
Detritus
Graffiti
Flyposting
All Land Uses
24
31
13
4
Main Retail/Commercial
30
7
10
18
Other Retail/Commercial
17
4
22
9
High Obstruction Housing
37
50
3
4
Medium Obstruction Housing
15
28
3
1
Low Obstruction Housing
19
23
16
4
Industry/Warehousing
41
57
24
0
Main Roads
13
22
7
4
Rural Roads
24
42
7
0
Other Highways
34
35
30
3
Recreation Areas
11
53
10
1
16.5.5 Authorities should be aware that most quality inward investors – those who intend to invest for the long term – judge local authorities on the environmental standards that they perceive when travelling around the district, especially in places where they may be considering making investments, including industrial and warehousing estates.
16.5.6 By concentrating priorities on land uses with the highest scores for the different elements of NI 195, over a period of time authorities should gradually be able to reduce the proportion of sites graded below B.
16.5.7 A typical progression is shown in Figure 16.5.1 below (a real-life example), where over a long period managers have consistently focused attention on the sites with the worst standards in relation to litter. At Stage 1, the majority of sites were either moderately or heavily affected. By Stage 5, the majority of sites were either clean, or only lightly affected.
Figure 16.5.1
16.5.1
16.5.8 Regular Review of NI 195 Results
NI 195 is structured so that it can be used either as a series of single surveys; as an annual survey; or as a ‘rolling’ annualised survey.
16.5.9 If used as a rolling annual survey, as every four-monthly set of results is added, the results for the equivalent period in the previous year can be deleted from the calculation (but not from the database!). This option allows authorities to monitor changes in standards closely, and adjust cleansing resources, priorities and strategies accordingly.

16.6

What is The Margin Of Error Associated With NI 195 Results?
16.6.1 The NI 195 survey is structured so as to minimise the possibility of it being biased in some way (which is the same objective as that of a random sample).
16.6.2 In the Tables below, the margins of error associated with a random sample have therefore been be used as a guide to the likely margin of error for the ‘raw’ data (before giving a half-weight to the B – grades) from the NI 195 survey.
16.6.3 Table 16.6.1 gives an indication of the likely margin of error for the overall annual NI 195 results (based on 900 sites), while Table 16.5.2 gives the same information for the individual four-monthly surveys (based on 300 sites). The margins of error below apply to the unweighted, ‘raw’ data extracted from the NI 195 database in BVPI 199 format.
16.6.4 In these tables, the true figure is likely to be within the margin of error estimated, 19 times out of 20.
16.6.5 This means that for a figure of 30% estimated from a sample of 900 transects, 19 times out of 20 the true percentage is likely to be in the range 27.0 to 33.0.
16.6.6 Whatever the margin of error, 30% will still be the most likely figure.
  Table 16.6.1 Annual NI 195 Survey (900 Transects)
Estimate (%) Margin of Error (% +/-) Possible Range (%)
30 3.0 27.0 - 33.0
20 2.6 17.4 - 22.6
10 2.0 8.0 - 12.0
16.6.7 Table 16.6.2 shows similar estimates of margins of error, based on a survey size of 300 transects (i.e. a NI 195 four-monthly survey).
  Table 16.6.2 Four-Monthly NI 195 Survey (300 Transects)
Estimate (%) Margin of Error (% +/-) Possible Range (%)
30 5.2 24.8 - 35.2
20 4.5 15.5 - 24.5
10 3.3 6.7 - 13.3
16.6.8 Individual Land Uses
At the level of individual land uses, the results of the NI 195 survey will give an indication of the ranking of land uses, as a basis for decisions on priorities for action.
16.6.9 Analysing Survey Results On A ‘Rolling’ Annual Basis
The online database will enable authorities to aggregate three four-monthly NI 195 surveys on a ‘rolling’ basis – i.e. the latest four-monthly survey can be combined with the two previous surveys to provide an analysis based on 900 transects overall, and 90 transects for each land use.
16.6.10 This will provide additional information to help assess trends, and help to guard against reacting to apparent swings in standards that may partly reflect random variations in the survey.

16.7

Setting Targets For Improvement
16.7.1 In setting targets for improvement in standards, or agreeing targets in the context of Local Area Agreements, authorities should normally identify targets over a period of some years – e.g. three years for Local Area Agreements. Interim (and final) results should be assessed in the knowledge that there may be some margin of error.


Last modified: 18 June 2009
Last published: 11 May 2009

Department for Environment, Food and Rural Affairs