Cleanliness National Indicator (NI 195)

Planning (cont.)

2.3

Survey Structure
2.3.1 The prime objective of a NI 195 Survey is to obtain, as far as is possible, a sample that is representative of the range of conditions that are to be found in each local authority. The surveys are therefore not based on random samples.
2.3.2 A ‘representative’ sample is one that, in its selection of transects to survey, seeks to reflect the different types of development that are present within a Land Use, within the authority.
2.3.3 Different types of development often reflect the age of development, which can vary in age from late Victorian/Edwardian, to the late 20th and early 21st centuries. Retail and Commercial, Housing and Industrial/Warehousing land uses usually all show this kind of variation.
2.3.4 Authorities should try to ensure that the NI 195 sample reflects such variations, where they exist, within the target wards.
2.3.5 This can be done either in planning each four-monthly NI 195 Survey, and/or by surveyors using their local knowledge to select transects on site.
2.3.6 Surveyors should also try to get a geographic ‘spread’ across the target ward, rather than concentrating all the transects for a particular land use in a small area.
2.3.7 In this way, the NI 195 survey will maximise the extent to which it reflects the variations that exist within an authority.
2.3.8 The NI 195 Survey therefore draws its samples from representative selections of electoral wards within an authority. The aim is to survey a set number of sites for each land-use that is present in the district. Sample sites (‘transects’) are drawn, as far as is practicable, from locations across the selected (‘target’) wards.
2.3.9 A new selection of five target wards is used for each four-monthly survey period. Using the methods described below, all wards in a district will be sampled in a planned rotation.
2.3.10 The use of a limited number of target wards has two objectives:
a. to ensure that, over a period of time, the survey is drawn as evenly as possible from all parts and types of area comprising a district; and,
b. to minimise the amount of travelling between transects on any one survey day, resulting in more productive use of staff time and reduced overhead costs.
2.3.11 It is recommended that the five target wards should be selected using:
a. the estimated 2004 Indices of Multiple Deprivation for electoral wards contained on the Sources of Information page on this website; and,
b. the set of ward boundaries that existed on 31st December 2002, to which those estimates relate. (For a minority of local authorities, the estimates refer to the set of wards that would be used for the local 2003 elections. In these cases, a Statutory Instrument had been issued before 31st December 2002, but had not yet come into force).
2.3.12 Alternatively, if the authority wishes to, it may use the 2007 Indices of Multiple Deprivation for Lower Level Super Output Areas (LLSOAs), adapting them to reflect current ward boundaries in the manner described in Section 2.2 above.

2.4

The Role Of Wards Within The NI 195 Survey
2.4.1 It is important to understand the role of electoral wards within the NI 195 Survey and what can and cannot be determined from the data.
2.4.2 The NI 195 Survey uses ward boundaries only in order to subdivide a local authority into sub-areas for survey purposes. The link to IMD allows a reasonable cross-section of areas to be surveyed across the range of deprivation within an authority. The NI 195 Survey is not designed to provide accurate figures at ward level, and should never be used for this purpose.

2.5

Survey Planning
2.5.1 The NI 195 survey planning system, outlined in the following sections of this Manual, takes account of the ways that land-uses are typically distributed within a local authority:
a. some land-uses are restricted in their distribution, and have to be surveyed wherever they exist. Good examples of these are Main Retail and Commercial Areas, and Industrial Areas;
b. some land-uses occur in some, but not all, electoral wards. The most common example is Medium Obstruction Housing;
c. some land-uses occur in all or most wards, such as Recreation Areas.
2.5.2 There are three steps in the survey planning system:
a. STEP 1 - selecting comparable groups of five target wards to be sampled during each four-month survey period;
b. STEP 2 - identifying and mapping the locations of relevant NI 195 Land Use Classes;
c. STEP 3 - scouting the selected wards to check the accuracy of desk-top work undertaken during Steps 1 and 2, and to identify locations containing more difficult-to-find land-uses, such as ‘Other Highways’.
  Within each target ward, surveyors should try to achieve a reasonable geographic ‘spread’ of survey sites, and of different types of development.

2.6

How Long Should Survey Planning Take?
2.6.1 The process described in the following sections should normally take the equivalent of one working day for two surveyors, once the necessary materials have been assembled (such as maps, listings of Indices of Multiple Deprivation, and locations of key land-uses). It is not necessary to have completed all the mapping before starting to survey, it is acceptable to complete the mapping in stages.
2.6.2 After a few survey cycles most local authorities will have compiled a definitive NI 195 land-use map of their district. Therefore, progressively less time will be needed for planning future surveys. However, periodic checks will be needed to monitor where, and what types of new development have taken place in the district and whether any developments have changed the prevailing land-use.

2.7

How To Plan For NI 195 Surveys In New Unitary Authorities?
2.7.1 A number of authorities may be affected by recent proposals to create additional Unitary Authorities. The normal principles used for NI 195 Surveys will be applicable for the new authorities, but may need to be adapted according to local circumstances including the proposed contents of Local Area Agreements.
2.7.2 Defra will be working with the new Unitary Counties during 2009/10 to trial different approaches to the NI 195 Survey. These will be reviewed at the beginning of 2010, and may be reflected in the next annual update to the guidance for NI 195.


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

Department for Environment, Food and Rural Affairs