Coordinated Assessmentand Information Management

Training 4 – 9 May 2014

HUMANITARIAN PROFILE

METHODS OF ESTIMATING AFFCTED POPULATION

Methods

• A total of five broad categories of population estimation methods have been identified.

• Every method has been organized in one of these categories: – Sampling methods – Site estimation methods – Counting methods – Remote estimation methods – Estimations using population data sets

Site estimation methods

• ’Guesstimates’ and community estimates • Many organisations make very rough

estimates (‘guesstimates’) based on visual assessments. This educated guess can only be done with some kind of visual picture of what, for example, 1,000 people looks like (UNICEF 2010).

Site estimation methods

• Key informants’ estimates (people and community leaders from the area, village elders, service providers, local authorities) can be important sources of information on population figures, family composition, household size, settlement patterns, and arrival and departure rates (CIEDRS 2003, UNICEF 2010).

Sampling methods

• Pre-crisis population size and location provides guidance on the areas to sample and

• the relative population sizes among villages (WFP 2007).

• If no detailed local maps are available it may be necessary to create them (e.g. displacement situations where refugee/IDP settlements are evolving) (CIEDRS 2003).

Sampling Method

Quadrat method • Obtain an aerial view or draw a map of the

area of interest• Measure the perimeter of the area.• Create a scale outline of the area

Sampling MethodQuadrat method • Measure the total area by counting the number of full

and partial quadrats.• Select a random sample of quadrats. (Head count)• Extrapolation: The average population density measured

in the sample quadrats can be extrapolated directly to the entire area for an estimate of total population size

• Alternative: A population is never regularly distributed equally among a camp. Population density is higher in the middle of the camp where most facilities are initially located, while it is dispersed at the periphery

Sampling: T-square method

• . Select a random point (WFP 2009). A number of points (P), typically 60, are distributed across the area using computer software (either randomly or systematically)

• Measure the distance from this point to the nearest occupied house (WFP 2009): from each point (P) the distance (d1) to the nearest house is measured

Sampling: T-square method

• Go to this house, find the occupied house nearest to it, and measure the distance (d2) between the two houses

• Count the number of people living in the two houses and calculate the average

• Estimate the total area of the survey• Calculate the average space occupied by these houses

and its surroundings• Calculate the total number of houses in the survey area

by dividing the total area of the survey by the average space occupied by each house and its surroundings

Household sample survey

• Sample selection• Survey• Analysis

Site estimation

Participatory mapping Participatory mapping of the catchment area may be done by inviting a group of the affected population to sketch a map of the entire community on the ground or on a large paper. The catchment area is the geographical area from which all the people attending a particular health facility come (IFRC 2007).

Site estimation

Focus group discussionsA focus group discussion entails organizing and conducting a group discussion while ensuring that the group is ‘representative’ of all segments of the (IDP) community (e.g. women, men, community elders, adolescents, IDP leaders). This method is useful in obtaining additional data and should be triangulated with at least one other source, such as good baseline data or a quantitative source. Useful data elements that can be collected are perceived size of the (IDP) population and perceived sex and age breakdown (OCHA and IDMC 2008).

Site estimation

Drive through / walk through A drive through involves driving through a disaster-affected area to assess the situation. Things to look for could include settlement patterns, quality of shelters, physical signs of distress (death, illness, conflict), household property (cooking facilities, livestock) and community resources (clinics, schools, wells) (CIEDRS 2003).

Site estimation

Water usage dataRelies upon the assumption that the population number in a camp can be estimated by the average amount of water used by each individual. Immunization /Food delivery data

Site estimation

Mobile crowd estimation Estimates the size of a mobile population in which people may join or leave the march at various points. The number of participants, N, in the demonstration is defined to be the number of people who entered the demonstration route.

Satellite imagery / Remote sensing

• Satellite images can allow for detailed camp area estimates during an emergency or crisis, but can also provide baseline data for an area which is susceptible to a shock.