When we think about
experiments, we tend to picture microscopes and beakers. The advantage of natural lab
experiments is that the research is in highly controlled environments where
they can isolate and manipulate variables. In contrast, social experiments
present more challenges because the research might use the wrong measurements, miss
controlling for an important causal factor, or use an incorrect method. However, in the policy realm it is crucial to
continue measuring the effects and impact of different factors in order to
provide politicians with information to design better public policies.
There has been a great deal of discussion among government officials and scholars about the most effective way to break the cycle of poverty, and one of the most popular methods is using Conditional Cash Transfers (CCT) programs. In these programs, money is given to a household that meets certain criteria. These are usually related to the children going to school or regular medical check-ups. I am especially interested in testing effects in education outcomes. I want to find out if a CCT has an effect on grade progression and if the increased demand in school enrollment led to success in school, which is measured by grade progression.
Honduras is the
second poorest country in Central America. In 1990, they implemented the Programa de Asignación Familiar or
Family Allowance Program (PRAF) CCT. The program, PRAF II, was redesigned to
improve previous weaknesses. To analyze the effect of PRAF on education
performance I used the difference-in-difference technique based on panel data
collected in a random experiment. To understand the validity of this
experiment, we need to understand its various components.
What was the sample framework?
In 2000, the Honduran
government conducted a randomized experiment in 70 of the poorest
municipalities of the country. The data was collected on every individual in
each program household in 2000 and 2002. The survey from 2000 was collected
before the program was implemented and the survey from 2002 was collected for
the current year.
Who was eligible for the program?
Education transfer
was available to families with children ages 6 to 12 who were enrolled and
regularly attended grades 1-4.
Health transfer was
available to families with children under 3 and pregnant others who regularly
attended health centers.
How are treatment and control groups
structured?
In order to have a good treatment group
there is a need to administer a large exogenous shock in a short period of
time. The PRAF experiment had a total number of 15,350, which consists of 7,675
individuals (each individual having been surveyed in both 2000 and 2002) and
3,935 households.
Ideally, we would
like to be able to compare the same treatment group and run the experiment again
without giving them the treatment. Since we are not able to do that because of
time restrictions, we need a counterfactual or control group that identifies
the outcomes that would have happened in the absence of the treatment. We
hope that random selection makes the groups as similar as possible. In this
experiment, child height-for-age was used as a poverty proxy to determine which
municipalities would be eligible for the CCT program. They employed a system of
geographic targeting to identify the communities where the chronically poor
lived. The program drew up a list of municipalities based on the findings of
the 1997 census and selected those whose chronic malnutrition indices fall
below a standard deviation from the mean.
Based on this
preliminary selection of eligible municipalities, a random statistical sample
was then made to assign those which fell into the treatment and control groups.
As a result, 40 eligible municipalities were assigned to treatment and 30 into
control. Any of those households from the selected treatment communities was
considered eligible for the transfer if it complied with the component
criteria. The quality of the estimate is mainly based on the similarity of the
counterfactual to the treatments group. Otherwise, the estimate will have bias.
How to assess impact in Education
performance?
The education system
in Honduras faces problems of general service provision, low teacher quality, low
enrollment rates and low performance. Children also tend to delay joining school,
and their age on entry exceeds the normal age at that grade level. Due to the levels of poverty in Honduras, it
is common that children have to work instead of going to school. Moreover, the
quality of the educational service is very poor.
The cash transfers in
the treatment group were available for families for each child age 6-12 who was
enrolled in the first four years of primary school and attended regularly. In
my test, I restricted the sample so that we are only examining children between
the ages of 6 and 12. The total observations were 2,648.
I used the
difference-in-difference technique because it allows me to measure the impact
with the data from the pre and post implementation of the program. This method
mimics an actual experiment by measuring changes in average outcome in the
treatment group before and after treatment minus the difference in average
outcome in the control group before and after treatment.
The program requires
enrollment and attendance in school in order to receive the cash. Therefore, it
will be expected that these two variables will increase because of the
pre-condition and not because it is a successful program. As a consequence,
only measuring these variables (enrolled or attendance) will not actually show
that the program is changing behaviors in children and improving the education
performance. In order to measure impact,
I used two models. The first one measures the difference in enrollment and the
second one that of grade progress.
It is important to
include in each model some characteristics that affect enrollment and grade
progress. I controlled for years of education of head of household,
distance to primary school, and size of household and household characteristics
such as floor composition, availability of electricity. In addition, I added the name of their municipality
and if they received support from welfare program that is not PRAF.
In my first OLS
regression using the variable “enrolled” I can prove that in fact there was an
increase of 0 054 and it is statistically significant.
However, to find
impact I applied the difference-in-difference formula to the “progressed”
variable. The results show that the difference was of 0.05 and this was not
statistically significant.
We can infer that even though the cash transfer motivated
parents to enroll their children in school, when accounting for the original
differences between the two groups and tracking those differences over time, we
see that there is no significance in the results. In consequence, it appears
unlikely that the PRAF program led to considerable improvements in grade
progression from 2000 to 2002.
Are my results valid?
The key assumption for any
difference-in-difference strategy is that the outcome in treatment and control
group would follow similar trajectories in the absence of the treatment.
Common trend assumption is difficult to verify
but using pre-treatment data could show that the trends are the same. Yet, even
if pre-trends are the same we still have to worry about other policies changing
at the same time. In this experiment, I cannot quantitatively demonstrate the
common trends assumption because I do not have pretreatment data. However, the
years previous to the experiment were not unusual. In other words, there was
not a big economic shock or other macroeconomic factors that could have
affected the municipalities included in this study. I am aware that PRAF was in
place in some of the municipalities since 1990, so even if I had data from
previous years the effect was already there. In addition, the number of
observations and the randomization effect should help to overcome the lack of
pre and post treatment data.
Conclusion:
Appendix:
I used fixed effects for municipality in order to control for any differences in the municipalities such as rural vs. urban, culture, weather, agricultural conditions, etc.
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