Toolkits for Urban Transport Development - UNEP

Addendum to Household Survey Formats
Sampling method note
The purpose of the household surveys is to quantify and analyze the travel characteristics of people
belonging to various socio-economic groups in the city. Besides, the household level survey will also
help in modelling origin-destination of trips, vehicle emissions and stated preferences etc. This survey
mainly captures the existing conditions of the respondents and their preferences or choices as stated
by them.
Sampling
Urban areas are large and highly diverse. An assessment of the full universe for an appropriate
sampling is itself a hard task, given that many of the available data from the census tracks, which can
be used for getting the characteristics of the universe, are not available in the public domain.
Secondly, for such large universes, a stratified systematic sampling is required provided we are able to
identify the strata from the available data set. Thereafter the task is to decide the strata for survey and
then identify samples within each stratum. More diversified the sample, more the strata identified and
better the identification of strata more representative the sample is. We discuss below the process of
identifying different strata and sub-strata in a city and then selecting sample households for detailed
structured questionnaire surveys.
1. Stratifying the city by spatial (geographic) units
The urban areas need to be selected for survey on the basis of unbiased spatial representation. The
first task is to identify the spatial units from within which the second level of stratification is done.
Based on the demographic characteristics and delineation of traffic analysis zones (TAZs), the first
level of strata can be identified. At the first level, the city can be divided into different spatial units
based on either population density or delineated TAZ in case the latter data are available. Since the
data of TAZs is not available, the demographic data has to be used.
For the use of demographic data, the hypothesis is: ‘people of same economic and social
characteristics congregate in the same area’ and that densities indicate economic characteristics of a
neighborhood. Population census gives the demographic characteristics and from among the available
data, four can be of use in combination or individually (i) housing characteristics – katcha housing
representing the poor and pucca housing representing the rich and the middle classes (ii) female
literacy rate – higher the income higher is the female literacy, (iii) density and (iv) proportion of
Scheduled Castes/ minorities.
The census has the data for each household but when the data is given out, it is by wards of the city.
Ward can be used as a basic unit of spatial stratification, if the wards are not too large. If the wards are
too large then we have to go at the sub-ward level and we need to find out from the Urban Local Body
(ULB) if it has this data. If it is not available with the ULB then one can use the data of the
enumeration block of the census, which is a data aggregated for about 100 to 120 households. This
data can be plotted on the map to get the spatial divisions and then pick up the strata for sampling.
This is the First Stage Stratification. Some of the cities now have a Geographic Information System
(GIS) data with building footprints and from mapping these; we can identify homogenous zones as
First Stage Strata (FSS). Since the demographic data are available at a micro spatial unit level, these
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