Welfare Impacts of Urban Expansion: Micro Perspective from Peri-urban
Northern Ethiopia
Tsega Gebrekristos Mezgebo1*
Mekelle University, Ethiopia
Abstract
Urban areas, in many developing countries, expand by engulfing the nearby rural
villages which causes a complete shift of policies and livelihoods in the villages. This
study examines the ex post impacts of urban expansion on welfare of subsistence farm
households included to urban locality. The study utilizes panel data of 457
households, collected in 2011 and 2012, from peri-urban Ethiopia. The descriptive
statistics shows that physical asset (land and livestock) holdings of farm households
included to urban have reduced. Using the difference-in-difference with matching, the
results show that consumption expenditure of the farm households included to urban
has significantly reduced over a year. The negative effects on asset holdings and
consumption expenditure is consistent with the perceived view of difficulties in
livelihood transitions and to accustom new institutions. This study supports broader
investments in rural nonfarm sector and institutions to address the vital challenges of
rural-urban livelihood transitions, and to manage the process and embrace benefits of
urbanization.
Keywords: difference-in-difference, farm households, matching, livelihood transition,
peri-urbanization, peri-urban, welfare, Northern Ethiopia
JDE Code: O180
1
Corresponding author’s contact: Email: tsegagi@gmail.com.
*
Data collection was funded by the Ministry of Agriculture and Rural Development of Ethiopia and Irish Aid for
Ethiopia. I appreciated the generous institutional support of University College of Cork, the Ethiopian
Development Research Institute and Mekelle University throughout the research process. I am grateful to
Tassew Woldehanna and Catherine Porter for their time and inputs. I also thank the seminar audiences of the
Ethiopian Development Research Institute, the 19th annual conference of the African Region Chapter of
Econometric Society, the 3rd annual conference on Tigray Regional State Economic Development, the 2014
conference on IGAD Economies and Somalia Federalism and the 2015conference on Centre for the Study of
African Economies.
1
1. Introduction
Urban areas of many developing countries, particularly in Africa, are expanding rapidly by
incorporating the surrounding rural villages (Chen, Gu, & Wu, 2006; Gregory & Mattingly,
2009). But the urban areas are surrounded by subsistence farming communities where ruralurban divisions are vital. Urbanization in sub-Saharan Africa (SSA) continues unabated
(World Bank, 2013) and is land intensive. For instance, about 20% of the African population
live in urban and is expected to reach 50% by 2040 (World Bank, 2013). This shows that
urbanization in SSA is at its early stage and possible to make it right if lessons from the past
are considered.
Urban expansion in the SSA is structurally different from that of the East Asian or the
developed countries. This is because food production has remained low (Jedwab, 2012) and
the manufacturing and service sectors are small and inefficient (Henderson et al, 2013;
Jedwab, 2012). It is also documented that urban areas of some SSA countries were expanding
against the backdrop of economic growth (Fay & Opal, 2000; Henderson, 2003).
What causes the rapid urban expansion (or urbanization) in SSA is ambiguous and needs
considerable debate. But at the early stages of development, economic growth and
urbanization are accompanied by raising income inequality (Kuznets, 1955). This signals the
poor gain little from the early stages of urbanization and becomes worse in cases where
urbanization outpaces economic development. Similarly, Henderson (2002) points out that
the rapid urbanization in developing countries has little space for the rural societies and
institutions to acclimatize themselves to the urban ones. These issues have vital implications
to subsistence farm households inhabited in the peri-urban areas (PUAs).
In fact some studies indicate that poor farm households likely to be vulnerable and
marginalized in the course of rura-urban livelihood transition (Gregory & Mattingly, 2009;
Mattingly, 2009). Additionally, in Ethiopia, moving out of poverty is more difficult to urban
poor than the rural (Bigsten & Shimeles, 2008). These issues suggest that urban expansion
induced poverty is likely to evolve in the peri-urban areas (PUA). Hence, it merits justifying
empirically the effects of urban expansion in Africa at micro level to guide policy for
possible interventions. But the knowledge on effects of urban expansion on welfare of the
farm households’ in peri-urban villages is very thin. Hence, this paper partly addresses the
2
knowledge gaps using panel dataset of farm households from PUA of Tigray, Northern
Ethiopia.
This paper has three main contributions. First, it provides further evidence on the effect of
urbanization on welfare of subsistence farm households in the pre-existing villages. It mainly
examines the effect of urban expansion on consumption expenditure and asset holdings of the
farm households. Assessing asset holdings has the advantage to capture other aspect of
household welfare rather than food deprivation. Second, it provides a case in a context where
land is owned by the state and expropriated for investments. Third, to the best of my
knowledge, this is the first study to apply ex post impact evaluation methods to examine the
effect of urbanization on the peri-urban villages at a micro level using panel dataset in the
context of SSA.
Benefiting from nature of the data, difference-in-difference matching methods (Heckman et
al., 1997) is applied to evaluate welfare effects of urban expansion at micro level. The results
show that the physical asset (land and livestock) holding of the farm households in urban
becomes lower and their consumption expenditure has significantly reduced over a year. The
analysis is organized as follows. The second part provides background information regarding
urban expansion process in Ethiopia while section three presents the econometric framework
applied to evaluate the effect of urban expansion. Section four discusses the data and terms
used for the analysis. Section five discusses estimation results of the empirical model while
section six presents conclusions and recommendations.
2. Urban Expansion and Peri-urbanization Processes in Ethiopia
Ethiopia is among the poorest and least urbanized countries in sub-Saharan Africa. But since
mid of 2000s, Ethiopia is achieving remarkable economic growth and urban population is
growing rapidly as well. For instance, average annual urban population growth was about 4%
in 2007 (Bane and Alemu, 2012) – which is twice of the growth rate of urban Africa
(Montgomery, 2008). This growth rate, if not larger, is expected to continue for some time
because urban Ethiopia is still home to less than 20% of its people.
Urban and rural divisions are still vital in Ethiopia with defined boundaries where the local
policies are focused within their boundaries with little room for coordination of activities. To
meet the growing demand of urban land use, urban areas usually redraw their boundaries by
incorporating rural sub-villages in the surrounding. Incorporation of the sub-villages to the
3
respective town/city administration is usually done in consultation with the rural
administration or the regional council. Demarcation of revised city/town boundary is enacted
after the respective development plan is approved by the local council (FDRE, 2008). This
procedure ultimately creates a new boundary to the town/city but eventually shrinks land
resources to the incorporated sub-villages.
But it is important to keep in mind that
landholding of the farm households is usually fragmented and within the village (locally
known as tabia). This means it is possible for the village, which was previously in rural
administration, to split into urban and rural administration after the new urban boundary is
demarcated. Consequently, some households in the urban may have farmlands in sub-villages
under the rural administration or the other way round.
In Ethiopia, land is owned by the state and the dispossessed household (individual) receives
land compensation when land is expropriated for investment purposes (FDRE, 2005). By the
law, the local authority has the mandate to expropriate land within its jurisdiction for
investment by giving prior notice to the landholder. Usually the practice is the household
receives cash as compensation to the lost property (land and/or housing). But the household
can use the land until investments by the other party starts although received compensation
and have no user rights.
The urban administration allocates the land under its jurisdiction for investments to different
entities. Subsequently, follows implementation of the investments such as construction of
new residential houses, institutions, manufacturing plants or installations of other urban
amenities. This is the stage where urbanization of the included peri-urban villages (or periurbanization) starts formally.
Peri-urbanization in Ethiopia, generally, follows a formal procedure where inhabitants of the
targeted (included) rural villages become urban inhabitants by law. In other words periurbanization, via land policy, affects the entire population of the targeted villages. This
implies these villages are now governed by the urban development priorities which is a
complete shift in their means of living. In situation like these, dispossessed farm households
likely face time and resource constraints to accustom themselves into urban livelihood
systems and to benefit from the emerging employment opportunities.
Implementation of the different investments virtually starts after two years since delimitation
of the new urban boundary. The rapid land use conversion– from subsistence agriculture to
industrial, residential and other urban purposes – creates heterogeneous social compositions
4
and economic structures in the urban peripheries. For instance, it is observed that new
residents mostly engaged in different sectors of the urban economy migrate to the locality;
subsistence agrarian activities overtaken by nonfarm activities within five years; new land
policies put in place and new land markets emerge resulting in commoditization of land and
housing. These transformations force the livelihoods in peri-urban areas to shift from farm to
nonfarm activities which ultimately affect welfare of the subsistence farmers in the locality.
Such types of transformations are apparent in the peri-urbanization experiences of many
developing countries (Simon et al., 2004; Webster et al., 2004).
3. Estimation Framework
Peri-urbanization, via the land policy, affects the entire population of the targeted villages.
Like any other policy interventions, peri-urbanization is considered as a program targeted on
the lives of farm households in the peri-urban areas. As described previously periurbanization in Ethiopia, and particularly in Tigray, follows a formal procedure. This means
inhabitants of the targeted sub-villages should comply with implementation of the urban
development plan by law. Hence, a household in the targeted sub-villages can hardly be
outside the treatment. The control group for such kind of policy intervention is known as
synthetic group (Abadie et al., 2010) and should have similar characteristics to the entire
population under the treatment but not affected by the treatment.
Empirical studies that focus on investigating the effect of social programs or interventions,
generally, apply families of “average-treatment-effect” (ATE) methods (Wooldridge, 2002).
The average treatment effects of peri-urbanization can be assessed using either matching
methods or regression model because selection model is unfit. Matching methods: are
complementary to regression; can identify the presence of sufficient overlap regarding
covariate distribution; and have diagnostics to assess their performance (Stuart, 2010). But
matching methods have no cure for perfect predictability of the matching index and for
selecting the right conditioning covariates (Stuart, 2010). Being cautious of the pros and
cons, matching methods is applied and ordinary least squares (OLS) for comparison
purposes. Formulation of the estimation model is presented next.
5
3.1 Estimation Model
To formulate the effect of peri-urbanization (the treatment) on welfare of the treated farm
households, i.e. outcome of the treatment: let
absence of the treatment. Similarly, let
be welfare of household
is the
at time
household welfare at time
in the
under the
treatment. Consequently, the welfare gain (or loss) of the treated household is given as
.
(1)
However, it is impossible to observe both outcomes,
concurrently which means
and
, for the
household
cannot be constructed because of missing data problem
(Wooldridge, 2002). But the counterfactual welfare (
can be generated from the control
group under some restrictive conditions2.
To account for participation in the treatment, a dummy variable is generated where
, if
the household is treated and
, otherwise. The sample units have two observations for
the outcome variable. Let
and
represent observations before and after the
treatment, respectively. The observed welfare for the treated household is defined as:
(2)
where
is the observed welfare and
is the counterfactual welfare. Therefore, in
hypothetical situations, the expected effect of peri-urbanization on welfare of randomly
selected farm households, i.e. “average treatment effect”, is specified as
. Similarly, the average effect of peri-urbanization on welfare of the treated farm
households, i.e. the “average treatment effect on the treated”, is given as:
(3)
When the treatment is completely randomized, then average treatment effect and average
treatment effect on the treated are identical. But most social experiments suffer from
selection bias arise from observed or unobserved factors.
2
The restrictive condition is known as ignorability of treatment which means conditional on the observables, x,
the outcome
is independent of the treatment,
, (Rosenbaum and Rubin, 1983). This implies
that
which is the average treatment effect conditional
on pscore, p(x).
6
Other than the treatment, the outcome variable (welfare) can be affected by confounding
factors, (
, specific to the household. Hence, the average effect of peri-urbanization on
welfare of the treated farm households conditional on observed covariates is defined as:
(4)
The second term on the right hand side of equation (4) is expected welfare of the treated farm
households had they not been include into urban administration, which is impossible to
observe. The standard approach is to match with welfare of the control group imposing the
conditional independence assumption (CIA) (Heckman et al., 1998). Rosenbaum and Rubin
(1983) propensity score matching method is applied to generate predicted probabilities of all
observables and to create comparable groups where entities with similar propensity scores are
considered as matches (Heckman et al., 1998). Hence, the propensity score is generated by:
(5)
where
is a propensity score (pscore) estimated using discrete choice model on pre-
intervention covariates,
, of the household that satisfy the CIA condition (Caliendo and
Kopeinig, 2008). The common support condition (
) is imposed to identify
sufficiently close matches and consistently estimate the average treatment effect (Wooldrige,
2002). Imposing the common support condition likely throws away observations in both
groups. Let this sample be represented by
which is a sub-sample of the total observations.
Hence, the average treatment effect on the treated in the region of common support is given
as:
.
(6)
Although matching eliminates bias due to observable differences, welfare can be affected by
unobserved differences peculiar to the household. Additionally, a set of criterion might have
been applied by the respective town administration to decide which rural sub-village should
be incorporated. Such decisions could possibly aim to maximize the economies scale of preexisting socio-economic infrastructures in the locality. This indicates that administration of
the treatment was not completely random although self-selection is not a concern. These
exogenous latent conditions of peri-urbanization decision are time-invariant but can be
sources of unobserved selection bias.
7
The difference-in-difference method (DD) is ideal to mitigate time-invariant selection bias
(Heckman et al., 1998; Galasso and Ravallion, 2004; Ravallion and Chen, 2005). However, I
have ex-post observations of the outcome variable and ex-ante and ex-post observations of
the confounding factors. Hence, the DD method cannot applied rather the model in equation
(6) is modified to estimate the outcome of interest. Accordingly, the effect of periurbanization on welfare of the targeted farm households over time in the region of common
support is defined as:
(7)
where
and
respectively;
are observed welfare for the treated groups for two consecutive years,
and
represent estimated counterfactual welfare generated from the
control group. Model (7) is similar to DD matching estimator (Heckman et al., 1997) and
applied to control selection on observables and time-invariant unobserved factors.
4. Data and Descriptive Statistics
4.1 Data, Terms and Definitions
The data were collected in January 2011 and 2012 from farm households in peri-urban areas
of Tigray, northern Ethiopia. Four out of ten big towns in Tigray Regional State ‒ namely
Mekelle city and Adigrat, Axum and Alamata towns ‒ were selected for survey purposely
(see Figure 1 for location) considering population , size of the economic activities and natural
resources endowments. These differences have the potential to capture type, pattern and
employment opportunities available in the localities.
8
Figure 1: location of survey sites
Population has grown tremendously, at different rates, in all the selected towns (Table 1). For
instance, the 2007 population census of Mekelle is more than double that of the previous
1994 census which is exceptional. It represents a population explosion which needs to be
explored but it is outside the objective of this study. Although annual population growth rates
of Axum and Adigrat towns are comparable, availability of land for expansion seems limited
in Adigrat.
Table 1: Area and population distribution of the survey towns
Area in km2
Town/woreda
1994
2007
2011
1994
2007
2011
Population
growth rate
1994-2007
Mekelle
20.34
102.4
192
97
216
261
6.5
Adigrat
NA
18
18.77
37
58
70
3.5
Axum
7.78
17.28
18.12
27
45
54
4
Alamata
NA
4.7
9.46
26
33
40
1.8
Population size (in 000s)
Source: compiled from CSA (1995); CSA (2010a); CSA (2011b); BoFP (2011a); BoFP (2011b) and the
respective administrations for area size of Axum and Alamata.
Note: Population figures of 1994 and 2007 represent census data while those of 2011 are projected population
sizes by CSA. Annual population growth rate is computed by the author. NA represents data not available.
9
The selected towns represent urban expansion situation of Tigray Regional State particularly
and Ethiopia generally for the following reasons. Firstly, the towns applied the land
compensation guidelines issued by the Federal Government of Ethiopia (FDRE, 2008) which
is uniform and fail to properly account irreversible investments on the farmlands. Secondly,
the scale and type of land compensation given to the dispossessed farmers varies depending
on revenue of the town. There other is the towns differ in terms of size of economic activities,
access to infrastructure and information, market size, population, and agricultural production
potential of the adjacent rural districts (locally Known as woreda).
After selecting the towns, villages (locally known as tabias) were selected from the adjacent
woredas of the respective towns. Selection of tabias was done in collaboration with the
respective woreda administration units. Level and direction of the town’s expansion was the
main criteria used to select the tabias and, then subsequently, the sub-villages. However,
households were randomly selected from each sub-village.
Each survey site (town) has its own control and treatment groups. The treatment group
consist farm households in the sub-villages under urban administration, hereafter known as
rur-urban households3, who: (i) officially recognized as urban residents before 2009; (ii) gave
up fully or partly their farmland between 2006 and 2009; and (iii) received land
compensation before 2010. Additionally, the treatment group was drawn from inhabitants
either born in or related via marriage to minimize self-selection problems.
The urban expansion policy of Ethiopia affects the entire population of the targeted (sub-)
village where treatment non-compliance is impossible. Following Abadie et al (2010), the
(synthetic) control group were drawn from the sub- villages adjacent to the treatment group
for two reasons. Firstly, both groups would have been in similar situations without urban
expansion (treatment). The other reason is that sub-villages, where the control group was
drawn from, are prospective targets when the next town expansion plan is considered. The
treatment and control groups were drawn from the sub-villages located within 15kms from
edge of the city/town built up.
The surveys were commenced towards end of the main harvest season in the agricultural
calendar of Tigray Regional State particularly and Ethiopia generally. A panel data of 478
3
The word rur-urban created from two words – rural and urban – to represent the households’ living style and
the administration they belong to, respectively.
10
farm households were observed and the dataset consists of details of the household’s
demography, asset holding and consumption. Additionally, ex-ante (2006 same period) asset
holdings of the household were collected to account for pre-intervention covariates.
Rainfall and inflation are crucial for the households’ welfare in subsistence farming
communities. The volume and distribution of rainfall in the wet season (kiremt4) is crucial to
food security of the subsistence farmers. According to the respondents, in all the survey sites
except Axum, the amount and distribution of rainfall in kiremt 2010 was good but in
2011rainfall started late and stopped earlier than the usual. As a result, agricultural
production in southern and eastern parts of the region was negatively affected which in turn
had direct negative impact on food security of the households, particularly in 2011/2012.
On the other hand, inflation was rising in 2010 in the nation. To curb the rising inflation,
particularly on food items, the Federal Government has introduced price ceiling for about 18
commodities in January, 2011 and removed in July, 2011 for most of the goods (Mesfin,
2011). But introduction of the price caps was counter-intuitive and exacerbated inflation, i.e.
inflation had reached to 40% in July, 2011 from below 20% in January, 2011 (Figure 2).
Figure 2: Inflation rate in Ethiopia, 2010 - 2012
Note: the figure is adopted from www.tradingeconomic.com| Central Statistics Agency of
Ethiopia (CSA)5.
4
5
The wet season (locally known as kiremt) stats in June and stops in September.
Accessed via: http://www.tradingeconomics.com/ethiopia/inflation-cpi
11
Terms and Definitions
The household’s food consumption expenditure was collected on a weekly recall basis from
all sources such as purchased, own produce, transfers and gifts. The local market price was
used to convert consumptions from non-purchased sources. The 7-day recall is effective
compared to longer recall periods although not free of errors from recall or expenditures
outside the purview of the respondent (Beegle et al, 2012). Expenses on non-food
consumable items were collected on a monthly recall basis and purchase frequency of each
item for the year. School and medical expenses are excluded from the expenditure list because
mostly available for free or at subsidized price and might not reflect the true value if
collected.
The monthly food expenditure was constructed from the weekly data and adjusted to
December 2010 prices using consumer price indexes of the Central Statistical Agency of
Ethiopia (CSA). To capture sex and age composition of the household, consumption
expenditure is constructed in per adult units using indices of Dercon and Krishnan (1998).
The farm household’s ex-ante asset holdings are also in per adult units. But it is important to
note per adult units cannot fully capture the scale of economies gained from the joint
consumption of housing services and durable goods available in the household.
The household’s livestock ownership is represented in constant prices and tropical livestock
unit (TLU). Local market prices, as proxy to farm gate prices, are adjusted for inflation using
the CSA producer price index (PPI)6. However, the TLU indices do not have conversion
factors for cross-breed/high-yield cattle (see Annex 2). Hence, indices for local breed are
applied to compute the corresponding TLU of all cattle breeds which understates the TLU of
improved or high-yield cattle breeds.
4.2 Descriptive Statistics
Farmland and livestock ownership of the rur-urban households has reduced between 2006
and 2012 (Table 2). The rural households’ livestock ownership has increased while size of
farmland has decreased between 2011 and 2012 although larger compared to rur-urban
households. Both groups had similar landholdings in 2006, on average, except in Adigrat
6
All values are represented in ETB and in December 2010 prices. The database is accessible via
www.csa.gov.et .
12
where rur-urban households have bigger farmlands than their counterpart. The proportion of
landless farm households, in general, increased over time for rur-urban households but
relatively unchanged for the rural. Peri-urban Adigrat has the highest proportion of landless
households ‒ about 65% of the rur-urban farm households have become landless due to urban
expansion ‒ and the smallest landholdings compared to the other peri-urban areas. This
indicates, relatively, peri-urban Adigrat is densely populated which concurs with the CAS
data (see Table 1).
Table 2: Distribution of farmland and livestock holdings by year and group
Rur-urban (treatment)
Rural (control)
2006
2011
2012
2006
2011
2012
Landless HH (%)
3.98
(2.05)
2.36
1.85
(1.68)
11.81
1.90
(1.58)
9.76
3.38
(1.90)
4.8
3.22
(1.96)
4.8
3.15
(1.98)
4.92
Observation (N)
127
127
125
125
125
122
Landless HH (%)
2.15
(1.51)
15.91
0.29
(0.54)
70.47
0.27
(0.54)
70.73
1.42
(1.06)
9.09
0.99
(0.94)
23.26
1.04
(0.97)
23.68
Observation (N)
44
44
43
43
43
39
Landless HH (%)
3.84
(2.05)
2.56
1.15
(1.08)
30.77
1.15
(1.09)
31.58
3.60
(1.55)
7.69
3.61
(2.06)
5.13
3.70
(2.00)
2.63
Observation (N)
39
39
37
39
39
37
Landless HH (%)
3.70
(2.04)
3.33
2.45
(1.69)
6.67
2.45
(1.69)
6.67
2.75
(1.91)
6.67
2.67
(1.97)
10
2.75
(1.97)
7.14
Observation (N)
30
30
30
30
30
28
Household head main job farming (%)
62.08
46.25
36.59
68.9
70.1
61.94
Livestock in TLU
3.86
(3.96)
2.63
(3.04)
6.76
(11.5)
2.62
(3.09)
6.26
(9.62)
3.13
(2.80)
3.14
(2.64)
6.64
(6.99)
3.15
(2.67)
8.14
(9.34)
240
240
234
238
238
227
Mekelle town
Average land holding per HH
Adigrat town
Average land holding per HH
Axum town
Average land holding per HH
Alamata town
Average land holding per HH
Real Livestock value (in 000 ETB)
Total observation
Note: landholding is represented in tsimdi (1 tsimdi ≈ 0.25 hectare). ETB is Ethiopian currency (1USD was
equivalent to 16.54ETB and 17.23 ETB on average during the first and second survey periods). Figures
in the parenthesis represent standard deviations.
13
Farming as main job of the household head generally decreased between 2006 and 2012. For
instance, it has decreased from 62% in 2006 to 37% in 2012 for rur-urban but for rural
households it decreased from 71% to 62%. This concurs with the observed trends for
livestock and farmland ownerships. Although access to farmland is being limited, many rururban households still consider farming as the main source of living.
Distributions of the pre-intervention variables (covariates) are presented in Table 3. The
covariates distributions of the treatment and control are similar except few namely age of
household head, old aged members and number of rooms per adult. The rur-urban farm
households have older heads and more old age members and number of rooms compared to
their rural counterparts.
Table 3: Sample means and standard errors of pre-intervention covariates
Treatment
Control
Difference
Variable definition
Mean (Std.)
Mean (Std.)
Mean (Std.err)
Household head age
50.59 (1.53)
43.53 (13.52)
-7.06*** (1.33)
Number of adults
3.02 (1.69)
2.84 (1.51)
-0.17 (0.15)
Number of children below 15 years old
2.15 (1.75)
2.33 (1.77)
0.18 (0.16)
Number of adults above 65 years old
0.24 (0.49)
0.07 (0.27)
-0.17*** (0.04)
Livestock in tropical units (TLU) per adult
0.80 (0.85)
0.77 (0.85)
-0.08 (0.07)
Farmland in tsimdi per adult
1.00 (0.98)
1.02 (1.07)
0.01 (0.09)
Number of rooms per adult
0.72 (0.81)
0.65 (0.70)
-0.32*** (0.06)
Female headed households (%)
0.30 (0.03)
0.26 (0.03)
-0.04 (0.04)
Household head farming main job (%)
0.62 (0.03)
0.69 (0.03)
0.07 (0.04)
0.60 (0.03)
0.55 (0.03)
0.05 (0.05)
Adult literacy and church school (%)
0.80 (0.02)
0.10 (0.02)
0.02 (0.03)
Completed grade 1-4 (%)
0.13 (0.02)
0.17 (0.02)
0.04 (0.03)
Completed grade 5 plus (%)
0.19 (0.03)
0.18 (0.02)
0.00 (0.04)
Household head level of literacy:
Illiterate (%)
Sample size(N)
240
238
Note: Std. represents for standard deviations, Std.err represents standard errors and *** means significant at 1%.
In 2011, consumption expenditure of the treatment group was significantly higher than the
rural households (Table 4). A year later, however, consumption expenditure of the treatment
group has significantly decreased while for the control consumption it has improved although
statistically insignificant. This shows that, on average, welfare of the control group has
14
improved over a year while that of treatment group has reduced. This suggests that welfare of
the rur-urban farm households might be systematically affected by the treatment (i.e. periurbanization) instead of differences in the observed covariates.
Table 4: Mean and Standard error of consumption expenditure
Treatment
Expenditure in 000 ETB
Real expenditure per adult
Real food expenditure per
adult
Real non-food expenditure
per adult
2011
2012
Mean
Mean
Control
Difference
(Y1)
***
2011
2012
Mean
Mean
3.42
4.07
Difference
(Y0)
0.16
Double
difference
( Y 1 - Y 0)
-0.96***
4.24
3.93
-0.78
(1.92)
(1.77)
(0.16)
(1.52)
(2.06)
(0.18)
3.42
3.15
-0.46***
2.96
3.42
0.29
(1.55)
(1.38)
(0.13)
(1.31)
(1.77)
(0.15)
(1.68)
0.83
0.78
-0.32***
0.49
0.66
0.13**
-0.20***
(0.71)
(0.61)
(0.05)
(0.40)
(0.56)
(0.06)
(0.06)
(0.20)
-0.76***
Sample size (N)
240
236
238
227
Note: figures in parenthesis indicate standard errors, *** is significant at 1% and ** is significant at 5%.
Availability of basic infrastructures such as school, market, road and health centers in the
sub-villages are important to ensure if the two groups are comparable. Although no ex ante
data for the amenities, ex post data is used to address the issue. The basic social services7
such as market, school, health center and veterinary are located in less than an hour walking
distance in 2011, except in Mekelle (Table 5).
The rural households are a little farther away from the service stations particularly secondary
schools. Although the travel time to services seems longer for the rural households, it is
important to note that the differences are less than half an hour on average and usually people
in urban are nearer to services than rural. In fact, in 2012, most of the sub-villages in the
control group have been incorporated to the respective town administration as part of the new
development plan. This signifies that the sub-villages in the control group are in a situation
7
Elementary school (i.e. grades 1 to 4 and grades 4 to 8), health clinics, veterinary posts and village (tabia)
administration centers are usually located nearby to each other. Hence, distance to elementary school also
represents distance to those amenities as well.
15
where the sub-villages in treatment group before the intervention which substantiates
comparability of the groups.
Table 5: Distribution of distance to amenities in 2011, single trip in minutes walk
Mekelle
Adigrat
Axum
Alamata
Mean
Mean
diff.
Mean
Mean
diff.
Mean
Mean
diff.
Mean
Mean
diff.
To town center
85.49
(1.60)
18.14***
(3.0)
42.56
(1.92)
11.25***
(3.8)
31.15
(1.99)
23.33***
(3.0)
26.83
(2.03)
12.67***
(3.8)
To elementary
school
20.51
(0.79)
3.74***
(1.6)
22.36
(1.40)
9.27***
(2.6)
23.84
(2.12)
25.90***
(3.1)
13.58
(1.14)
2.83
(2.3)
To secondary
school
64.99
(2.58)
45.73***
(4.3)
49.66
(2.38)
15.23***
(4.5)
38.46
(2.61)
28.46***
(4.1)
31.67
(2.30)
23.67***
(3.6)
Obs. (N)
252
88
78
60
Note: Mean diff. represents the difference in mean travel time between control and treatment and *** represents
significance levels at 1%.
5. Estimation Results and Discussion
5.1 Propensity Score
The pre-intervention covariates were used to estimate the propensity score (pscore) to ensure
the covariates are free of contamination or anticipation of the treatment (Dehejia and Wahba,
2002; Caliendo and Kopeinig, 2008). The covariates consist of factors associated with
household welfare such as the household’s demographic composition and asset holdings and
the local environment. The household head is influential in the consumption decision of the
household. Hence, the household head’s age, sex, main job and education status are
considered. Family size is directly linked to consumption expenditure. Asset holdings (such
as farmland, livestock and housing) and location of the household are included in the model
to capture their indirect effect on consumption expenditure. Presumably, keeping other
factors constant, households with higher asset holdings have likely higher consumption
expenditures and vice versa. Similarly, the household’s production behavior is likely
influenced by the local environment where town dummies are used as the proxy.
16
A logit model is regressed on the above discussed pre-intervention covariates to generate the
pscore for matching, conditional on sharing similar pre-intervention covariates distributions.
Interpretation of the parameter estimates is not relevant because decision to participate in the
treatment is not an option. The estimation outputs of logit regression indicate that most
variables are insignificant (Table 6). But few variables such as age of the household head and
number of adults above 65 years old are strongly significant. Similarly, main job of the
household head and number of adults in the household are weakly significant. This indicates
that the treatment and control group are different with respect to the corresponding covariates
which is similar to the summary statistics presented in Table 3.
Table 6: Logit regression estimation results
Variable
Female headed households (yes=1)
Household head age
Household head literate (yes=1)
Household head farming main job (yes=1)
Number of adults
Number of children below 15 years old
Number of adults above 65 years old
Farmland in tsimdi per adult
Livestock in tropical units (TLU) per adult
Number of rooms per adult
Location: base category Alamata
Mekelle
Adigrat
Axum
Coefficient
0.34
0.03***
0.25
-0.43*
0.12*
0.04
0.89***
-0.19
-0.01
0.28
Std. Err.
0.25
0.01
0.22
0.24
0.07
0.06
0.34
0.13
0.12
0.18
0.02
-0.18
-0.08
0.31
0.38
0.38
Constant
-1.73***
0.58
Sample size (N)
454.00
2
Psuedo-R
0.07
2
LR
43.63
Log-likelihood
-292.76
Note: The sample size has reduced to 454 due to missing observation for some covariates.
*** , **
, and
*
represent significant at 1%, 5% and 10% respectively.
Following the logistic regression, the common support condition was imposed and five
optimal blocks with the same mean pscores are identified and the region of common support
17
is created in the range of [0.20, 0.95]. But pscore is a continuous variable which makes
impossible to get exact matches (Becker and Ichino, 2002). To overcome this problem, the
commonly applied methods include nearest neighbor, kernel and stratification matching
methods though one method is not preferred over the other.
To ensure robust estimation of the matching algorithms, balancing tests were conducted on
distribution the covariates before and after matching (see Table 7). The standardized mean
deviation of the pscore is about 9.5% before matching for all the algorithms and below 5%
after matching, the acceptable level of bias (Caliendo and Kopeing, 2008). This indicates that
the estimation results are robust to the different matching algorisms. After matching, the
pseudo-R2 decreased from 7.6% to 0.4% and p-values of the likelihood ratio tests become
insignificant. These tests ensure that the proposed model reasonably identifies the pscore in
terms of distribution of the covariates between the treatment and control groups.
Table 7: Matching quality indicators
Matching
Algorithm
Pseudo-R2
before
Pseudo-R2
after
LR 2 (Pvalue) before
LR 2 (Pvalue) after
SMD
before
SMD
after
LLMA
0.0759
0.004
47.58 (0.001)
2.95 (0.58)
9.5
2.9
KMB
0.076
0.004
47.58 (0.001)
2.33 (1.00)
9.5
3.7
NNMC
0.076
0.004
47.58 (0.001)
2.46 (1.00)
9.5
2.3
Note: Variables included in psmatch2 stata command are: hhsex98, hhage98, hhage2, hhedu98, hhjob98, hagb,
nadult98, nchildb1598, hhadt2, nadult6598, pfland98, ptlu98, proom98, Mekelle, Adigrat, axum
(definition of the variables is provided in Annex 3)
A: represents local linear matching with band width 0.02, biweght weighting and common support.
B: represents kernel matching with band width 0.04, biweight weighing and common support.
C: represents the nearest neighbor matching with replacement, caliber 0.03 and common support.
5.2 Estimation Output of Average Treatment Effect
The regression outputs of ordinary least squares (OLS) are reported in (Table 8). Although
magnitudes of the estimates are different, the sign and significance level of the point
estimates are similar to the matching within-stratum estimates. The single difference (i.e.
equation 6) and the double difference (i.e. equation 7) matching estimation outputs are
presented in Table 9. In general, the matching algorithms have produced similar estimation
outputs. All matching algorithms have bias below the acceptable level while the nearest
18
neighbor algorism has the lowest bias (Table 7). For this reason, the discussion focuses on
the estimation outputs of nearest neighbor matching. Discussions of the single and the double
difference estimation outputs of the average treatment effect on the treated (ATT) are
presented separately.
Single Difference
In 2011, on average, the rur-urban farm households’ consumption expenditure was
significantly higher than the rural households (Table 9). The results show that consumption
expenditure of the treated households has improved by about 800ETB where the major effect
(about 60%) is on food expenditure. In general, the results suggest that rur-urban farm
households were in a better position in terms of consumption expenditure compared to the
rural household. But the caveat is this result could partially reflect consumption bubble that
arises from utilizing the land compensation for consumption purposes because land
compensation was given mostly between 2007 and 2009.
In 2012, the rur-urban households’ consumption expenditure becomes lower than their
counterparts although not statistically significant. On average, food consumption expenditure
of the rur-urban households is not different from that of the rural households. The effect on
non-food expenditures is weakly significant suggesting that the rur-urban households’
consume higher compared to the rural households’. However, it should be noted that the rural
households’ expenditures on utility is understated because of the free access to alternative
sources (for instance energy for cooking) or lack of access (for instance telephone services,
tap water). Overall, the total consumption expenditure of both groups is not statistically
different indicating peri-urbanization has no effect on the welfare. Looking at the changes in
consumption expenditure between 2011 and 2012, however, the results show that the
consumption expenditure of the rural households catches up with that of the rur-urban
households. This in turn signifies the rural households able to sustain, if not improve, their
existing level of consumption while maintaining or improving their asset base.
Double Difference
From the single period matching estimates, it happens difficult to conclude what the effect of
peri-urbanization is. However, the double difference matching estimation output shows that
ATT is negative and strongly significant (Table 6). This indicates that, on average, the rururban farm households’ consumption is significantly decreased compared to their rural
19
counterparts. For instance, between 2011 and 2012, the rur-urban farm households’
expenditure decreased by about 1000ETB per adult of which expenditure on food
consumption comprises of about 80%. This in turn indicates that rur-urban households in the
poorest cohort are the worst affected by peri-urbanization.
In sum, the estimation results indicate that peri-urbanization negatively affects welfare of the
rur-urban farm households for the following reasons. The first is change in the production
behavior of the rur-urban farm households due to of peri-urbanization coupled with high
inflation. Most of the rur-urban households are net purchasers of the major food items and the
high inflation rate likely erodes their purchasing power a year later. Additionally, as observed
during the survey periods, most of the fields were under farming activities in 2011 while in
2012 the fields became active construction sites for nonfarm purposes. Secondly, the high
consumption expenditure in 2011 could be a reflection of spending the cash (land
compensation) and might run out with time if the household is unengaged in productive
employments. Thirdly, the households might not be motivated to save the cash in financial
institutions rather invested it on household durables ‒ i.e. saving interest rate was about 5%
while inflation rate was about 33% in 2011 (Geiger and Goh, 2012) ‒ then lack the resource
to finance their consumption.
20
Table 8: Ordinary least squares (OLS) estimation outputs of the treatment effect
Real food expenditure per
adult
Coef.
Std. Err.
Real nonfood expenditure
per adult
Coef.
Std. Err.
Year 2011
Treatment
463.99**
201.54
459.46***
Peri-urban Mekelle (rur-urban=1)
120.41
221.10
-56.02
Peri-urban Adigrat (rur-urban=1)
-177.88
370.07
-343.44***
Peri-urban Alamata (rur-urban=1)
-294.38
334.90
-384.73***
Constant
2962.25
85.14
497.54
R-squared
0.03
Obs.
478
Year 2012
Treatment
144.12
295.38
206.96**
*
Peri-urban Mekelle (rur-urban=1)
-511.94
287.89
-135.59
Peri-urban Adigrat (rur-urban=1)
-549.44
372.99
64.22
Peri-urban Alamata (rur-urban=1)
-458.51
400.12
-161.52
Constant
3424.07
118.20
657.54
R-squared
0.02
Obs.
459
Difference between 2011 and 2012
Treatment
-282.86
271.03
-269.31***
**
Peri-urban Mekelle (rur-urban=1)
-684.42
284.12
-66.52
Peri-urban Adigrat (rur-urban=1)
-503.25
487.12
412.80***
Peri-urban Alamata (rur-urban=1)
-197.00
358.96
235.33**
Constant
457.68
117.19
164.67
R-squared
0.05
Obs.
459
Note: ***, **, and * represents significance levels at 1%, 5% and 10%, respectively.
21
Real total expenditure per
adult
Coef.
Std. Err.
99.32
121.09
115.52
131.95
26.15
0.10
478
923.45***
64.39
-521.32
-679.11
3459.80
279.96
309.88
426.49
431.53
98.61
0.06
478
102.81
106.57
178.25
147.37
37.11
0.02
459
351.07
-647.53*
-485.22
-620.03
4081.61
359.91
353.57
487.28
507.31
137.54
0.01
459
92.91
110.10
165.97
110.68
38.87
0.06
459
-552.17*
-750.93**
-90.45
38.33
622.35
305.01
326.80
544.18
404.73
128.45
0.07
459
Table 9: Impact of urbanization on rur-urban farm households’ welfare
Year
Matching
Algorithm
N.
treatment
N.
control
LLMA
169
KMB
Real food expenditure
per adult
Real non-food
expenditure per adult
Real total expenditure
per adult
ATT
Std. Err.
ATT
Std. Err.
ATT
Std. Err.
222
375.95***
193.43
341.66***
74.55
717.61***
253.31
In 2011
(single Difference)
186
221
440.81***
177.86
376.71***
68.63
817.37***
211.91
C
181
221
460.14***
178.47
376.23***
69.46
836.37***
185.92
LLMA
173
222
-426.12**
219.90
175.59**
79.79
-249.55
261.81
186
221
-324.85**
204.66
197.33**
73.83
-127.52
244.79
181
221
-362.98*
201.15
196.29*
76.18
-166.67
241.52
173
222
-773.29
186
221
-765.65
NNM
In 2012
(single Difference)
KM
B
NNMC
Between
2011 and 2012
(Double Difference)
LLM
KM
A
B
C
***
247.16
-171.92
***
238.65
-179.23
***
***
91.11
-945.20
***
85.96
-944.88
***
***
278.08
***
261.52
***
NNM
181
221
-823.11
235.85
-179.93
86.67
-1003.04
261.41
Note: significance levels at 1%, 5% and 10% are represented by ***, **, and * respectively. Matching was done within stratum and the variables included in psmatch2 are:
hhsex98, hhage98, hhage2, hhedu98, hhjob98, hagb, nadult98, nchildb1598, hhadt2, nadult6598, pfland98, ptlu98 and proom98 (see variable definition in Annex 5.3).
A: represents local linear matching with biweight weighing, band width (0.05) and common support
B: represents kernel matching with biweight weighing and band width (0.04)
C: nearest neighbor matching with replacement, neighbour(10), caliper(0.03) and common support.
22
6. Conclusions
This paper has presented the effect of urban expansion on welfare of farm households
included to urban administration. Using panel data, collected in 2011 and 2012, from farm
households in peri-urban Tigray, Northern Ethiopia changes in physical asset holdings and
welfare (as measured in real consumption expenditure per adult) were analyzed. The
difference-in-difference matching method was employed to estimate changes in the
households’ consumption expenditure. The analysis is robust to selection of observables and
unobserved fixed effects.
The results show that urban expansion (or peri-urbanization) has diminished the physical
asset, particularly livestock and farmland, holdings of the dispossessed (rur-urban) farm
households. Availability of farmland is reduced due to nature of the peri-urbanization and
livestock ownership is positively associated with farmland in subsistent farming systems. But
this in turn suggests that the treated farm households, given their experience in the farm
sector, are not engaged in the dairy sector. Consumption expenditure of the rur-urban farm
households, in 2011, on average, was significantly higher compared to their counterparts. No
significant difference was observed between the two groups in 2012. However, the change in
consumption expenditure, between 2011 and 2012, is significantly lower for the rur-urban
households than their counterparts.
The rur-urban higher consumption, in 2011, might indicate consumption bubble resulted from
spending the land compensation (cash) for consumption purposes and being actively engaged
in farming activities in 2010. This partly signifies consumption based on asset-depletion. But
the reduction in consumption expenditure, after a year, is possibly due to the high inflation
coupled with limited resources to finance and/or being out of farming and inability to engage
in other productive activities.
It can be safely generalized that the rur-urban farm households’ consumption expenditure and
asset base has diminished over time. The analysis shows that the rur-urban households would
have been in a better condition had they continued farming with the privileges that their
counterparts have. This in turn signals the gradual development of urban-induced poverty in
the localities. Hence, it is imperative to review the existing land compensation packages and
design targeted interventions, particularly on urban agriculture and other business advices, to
mitigate the hurdles of rural-urban livelihood transitions and poverty.
23
Annex 1: Tropical Livestock Unit Indexes
Animal type
TLU index
Camel
0.1
Cattle
0.7
Sheep and goat
0.1
Horse
0.8
Mule
0.7
Donkey
0.5
pig
0.2
Chicken
0.01
Source: Adopted from Jahnke (1982)
Annex 2: Adult Equivalent Scales
Years of age
0-1
1-2
2-3
3-5
5-7
7-10
10-12
12-14
14-16
16-18
18-10
30-60
60 plus
Men
0.33
0.46
0.54
0.62
0.74
0.84
0.88
0.96
1.06
1.14
1.04
1.00
0.84
Women
0.33
0.46
0.54
0.62
0.70
0.72
0.78
0.84
0.86
0.86
0.80
0.82
0.74
Sources: Adopted from Dercon and Krishnan (1998)
Annex 3: Covariates included in the balancing test
Variable name
hhsex98
hhjob98
hhage98
hhage2
hagb
nadult98
nchildb1598
nadult6598
hhadt2
pfland98
ptlu98
proom98
Mekelle
Adigrat
axum
Alamata
Definition
Household head sex in 2006; dummy female=1, otherwise=0
Household head main job in 2006; dummy farming=1, otherwise=0
Household head age in 2006
hhage98 squared
an interaction term for hhjob98 and hhage98
Number of adults in the household in 2006
Number of children below age 15 in the household in 2006
Number of adults age 65 plus in the household in 2006
nadult6598 squared
Household farmland ownership in tsimdi in 2006 per adult
Household livestock ownership in TLU in 2006 per adult
Number of rooms owned by the household in 2006 per adult
Dummy for Mekelle town peri-urban, Mekelle=1, otherwise=0
Dummy for Adigrat town peri-urban, Adigrat=1, otherwise=0
Dummy for Axum town peri-urban, Axum=1, otherwise=0
Dummy for Alamata town peri-urban, Alamata=1, otherwise=0
24
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