Disclaimer for Datasets
The data presented for the mVAM Ebola-affected countries from late September 2014 to present
has been collected using text message (SMS) and Interactive Voice Response (IVR) technology. As
per standard survey procedures, respondents’ consent was obtained prior to the interviews, and
an airtime credit incentive, in line with best practices for this form of data collection, was provided
to respondents following the survey.
When interpreting the datasets, readers are cautioned to note that mobile phone surveys will
skew towards better-off households in urban areas and for SMS data collection, specifically those
respondents who are literate. While the rate of cell phone usage is rapidly increasing, a large
segment of the population in each country does not own a cell phone and thus is not reached by
the survey. Remote data collection will not replace the need for on-the-ground emergency
assessments, particularly those used for targeting and response design. Coping strategies and food
price data collected through mobile have more variation than traditionally-collected data. When
reported, WFP focuses on large, statistically significant trends rather than on smaller variation. The
mVAM team further strives to triangulate information from other sources.
In line with best practices for SMS surveys, the questionnaire must be short and simple to ensure
satisfactory completion rates. For Rounds 1-3 of data collection (October-December), questions on
food prices and wage rates are not asked to the same respondents for this reason. This choice may
lead to additional variation in calculating the wage-to-food terms of trade. From January 2015
onwards, the survey has been condensed, with questions on food prices and wage rates asked to
all respondents. The complete questionnaire used from Round 4 (January 2015) to present is
listed at the end of this document.
Reduced Coping Strategies Index (rCSI)
The reduced Coping Strategies Index (rCSI) measures the frequency and severity of the behaviors
households engage in when faced with food shortages. It assesses whether there has been a change in
the consumption patterns of a given household. The rCSI is calculated using standard food consumptionbased strategies and severity weighting. A higher score indicates that households are employing more
frequent and/or extreme negative coping strategies. For more details on the calculation, please see the
Coping Strategies Index Field Methods Manual.
Commodity Prices, Manual Labour Daily Wage Rates and Terms-of-Trade
Experience has proven that price information is less variable when respondents are asked to report
prices in smaller quantities. In Sierra Leone and Liberia, respondents are asked to report the price of
imported and local rice in cups and are asked the price of palm oil in pints. In Guinea, respondents are
asked to report the price of imported and local rice in kilograms and are asked the price of palm oil in
half-litres.
Respondents are also asked to report the current daily wage for manual labour in their community.
Terms-of-trade are calculated by dividing daily wage rates by the price of the three commodities
(imported rice, local rice and palm oil) and are reported as the unit of a commodity that can be
exchanged for one day’s worth of manual labour.
Open-Ended Question
As part of round two (Guinea) and round three (Sierra Leone + Liberia) data collection, respondents in
Sierra Leone were given the opportunity to share a comment with WFP through an open-ended
question that read, “Do you want to share any additional information with us?” In January 2015, the
question was modified to say, “Tell us about the food situation in your community”.
Methodology for Data Cleaning
• Collected price data is crowd sourced from the general public and is not elicited from traders/markets.
• For both SMS and IVR surveys, respondents replied using the keypad on their mobile phone. In the
case of SMS surveys, respondents were able to see their typed replies prior to sending. For IVR surveys,
however, respondents’ replies were automatically registered.
• When cleaning all price data, common errors were observed and either corrected or removed.
The two most common errors were: 1) missing or extra zeros for prices; 2) irregular number sequences
(i.e., 45678 or 3333).
• Outliers (figures that were extremely high or low compared to the mean and median) were removed
from the price data.
• For rCSI data, outliers of 56 have been excluded from calculations.
Mode Effects
Following a comparison of the first two rounds of data collection, it is plausible that IVR results in higher
estimates of rCSI than SMS.
• When data collection in Liberia transitioned from IVR to SMS, an eight-point drop in the mean rCSI
was observed.
• In Sierra Leone, where SMS was used for data collection in both rounds, a much smaller twopoint
drop was observed over the same timeframe.
• In Lofa County, Liberia, where SMS was used during both rounds, the drop in the rCSI was below one
point.
• To test this theory, we would ideally want to sample the same population using both methods at the
exact same time.
• WFP’s objective is to shift to SMS when and where technically possible.
Dataset Interpretation
When interpreting the data from round 3 onwards, all country-level figures (rCSI scores, coping
strategies’ percentages, and price data) are calculated using population weights. Population figures
are taken from the Comprehensive Food Security and Vulnerability Analysis (CFSVA) data collected
by WFP for Liberia (2010), Sierra Leone (2011), and Guinea (2012).
Sample Sizes
For round 1-3 of data collection, the following sampling methods were used:
Country
Administrative Zones to
be Sampled
Sampling Requirements
Guinea
All
400 (IVR), of which 100 from Nzerekore
Liberia
All
800 (SMS), of which no less than 100 from Lofa and 100
from Montserrado
Sierra Leone
All
800 (SMS), of which no fewer than 100 from Kailahun
and 100 from Kenema
Total
2,400
In January 2015 round 4, the sample size and targeting was increased as per the following:
SIERRA LEONE (data collection by SMS)
Zone
Number of
samples
required
Bonthe + Pujehun + Moyamba
140
Bo
120
Bombali + Tonkoli + Koinandugu
150
Kailahun + Kono
120
Kenema
100
Kambia + Port Loko
140
Western rural
100
Western Urban
150
TOTAL SAMPLES REQUIRED
1020
LIBERIA (data collection by SMS)
Zone
Number of
samples
required
Bomi + Grand Cape Mount + Gbaroplu
100
Bong
100
Grand Bassa
100
Grand Kru, Maryland
100
Lofa
100
Margibi
100
Montserrado
350
Nimba
150
TOTAL SAMPLES REQUIRED
1100
GUINEA (data collection by IVR)
Zone
Number of
samples
required
Conakry
70
Boke
30
Kindia
50
Labe
45
Mamou
30
N’zerekore
70
Faranah
45
Kankan
95
TOTAL SAMPLES REQUIRED
435
In Guinea, polling with IVR was halted after January 2015 and recommenced with SMS in June 2015.
The table below shows sample targets by region for SMS polling June 2015 and on.
GUINEA (data collection by SMS)
Zone
Number of
samples
required
Conakry
125
Boke
100
Kindia
100
Labe
100
Mamou
100
N’zerekore
125
Faranah
100
Kankan
195
TOTAL SAMPLES REQUIRED
945
SMS Questionnaire for Liberia
Q#
Q Name
1
Birth Year
2
Sex Head of
Household
3
Toilets
4
Less expensive food
In the past 7 days, how many days did your household rely on less preferred or
less expensive food due to lack of food/money? [Reply number of days 0-7]
Borrow and get help
In the past 7 days, how many days did your household borrow food, or rely on
help from a friend or relative due to lack of food/money? Reply number of days
0-7
5
English
In what year were you born? [Reply with a four-digit number like 1980]
Is the head of your household a man or a woman? [Reply with 1 or 2] 1) Man 2)
Woman
What type of toilet does your household use? [Reply with a number] 1)Own
flush toilet 2)Shared flush toilet 3)Cement pit latrine 4)Dirt pit latrine 5)Bush
6
Reduce number of
meals
In the past 7 days, how many days did your household reduce the number of
meals eaten in a day due to lack of food/money? [Reply number of days 0-7]
7
Limit portion size
In the past 7 days, how many days did your household limit portion sizes at
mealtime due to lack of food/money? [Reply number of days 0-7]
8
Restrict consumption
In the past 7 days, how many days did your household restrict consumption by
adults so children could eat due to lack of food/money? [Reply number of days
0-7]
9
Manual labor
Currently, how much are people paid per day for manual labor in your
community? [Reply with the amount paid per day for manual labor in liberian
dollars]
10
Imported rice 1 cup
Currently, how much does 1 cup of butter rice cost in your community? [Reply
with the amount you pay for a 1 cup of butter rice in liberian dollars.]
11
Local rice 1 cup
Currently, how much does 1 cup of country rice cost in your community? [Reply
with the price of 1 cup of country rice in liberian dollars]
12
Palm oil pint
Currently, how much does 1 pint of palm oil cost in your community? [Reply
with the price of 1 pint of palm oil in liberian dollars]
13
Open Ended
Tell us about the food situation in your community. Type a short message (160
characters or less). If you do not want to respond, reply 2 to end the survey.