were more likely to be literate as adults. Other studies in Jamaica and China found deworming
improved children’s scores on memory and cognition tests (Simeon et al. 1995; Nokes et al.
1999).Miguel and Kremer (2001) evaluate a programme of bi-annual school based treatment
for worms with inexpensive deworming drugs in Kenyan schools. In this impact evaluation, 75
schools were phased into the programme in random order. They show that health and school
participation increased at treatment schools, but that positive externalities were also generated
for nearby control schools through reduced disease transmission. Absenteeism in treatment
schools was significantly lower than in control schools, and they estimate that the programme
increased schooling by 0.15 years per treated person. Finally, they also argue that what makes
deworming such an attractive intervention strategy is that it is very cost effective relative
to other interventions that provide free uniforms, textbooks or nutritional supplementation.
13 Bobonis et al (2002) find similar results in India as reported above.
7.1.4 HIV/AIDS
Given the AIDS pandemic across most African countries, this is one area where understanding
the link between health and productivity becomes especially important. There have been a
number of papers that have examined the economic effects of HIV/AIDS or the provision of
ARVs on productivity. These studies are complicated with the difficulty of randomizing HIV
status or of ARVs due to obvious ethical issues. Several studies have used other approaches to
examine the long run effects such as matching or using quasi-experimental techniques (Hab-
yarimana et al. 2008; Thirumurthy et al. 2005). Habyarimana et al (2008) find a significant
reduction in worker absenteeism in the year following the introduction of ARVS in the work-
place, and argue that for the typical manufacturing firm in East and Southern Africa, the
benefit of providing ARV treatment to workers covers up to a third f the cost of treatment. Us-
ing longitudinal survey data from Western Kenya, Thirumurthy et al (2005) show that within
six months of beginning ARV treatment, adult ARV recipients are 20% more likely to partici-
pate in the labour force, and they increase their weekly work hours by a third. Moreover, they
argue that these estimates are, in fact, an underestimate, since in the absence of treatment,
worker productivity would have declined even further. Hence, the upper bound of the impact
of treatment is larger. Thirumurthy et al (2005) also find that once adult AIDS patients within
the household begin treatment, young boys within the household work fewer hours in the labour
market, thereby potentially yielding positive outcomes for school attendance and attainment.
Evidence concerning the impact of HIV status on child outcomes is scant, but Brown et al
(2000) argue that HIV status in children is associated with delays in language acquisition, and
to the extent that this translates into educational penalties, will affect later labour market
prospects. Moreover, many children have been orphaned by AIDS, and thus find themselves
vulnerable and often living in chronic poverty. This impacts their developmental potential since
they have reduced access to resources and must deal with a great deal of psychological stress.
Case and Ardington (2006) show that orphans are less likely to be enrolled in school, and if
they are in school, they lag behind children of the same age.
7.1.5 Other health interventions
There are numerous other kinds of health interventions that might potentially also yield pos-
itive impacts on productivity and incomes later in life. For example, the effects of indoor air
pollution due to use of cooking fuel within a household has been suggested to be an important
factor in economic productivity (Duflo, Greenstone and Hanna 2008). Malaria may also reduce
productivity and there have been a number of papers that have examined the effects through
non-experimental methods (Ashraf, Fink and Weil 2009). In terms of supplementation of other
micronutrients, the evidence is either insufficient with more randomised control trials being
13 Since several programme interventions were conducted in Kenya in similar environments, they are able to
make cost-benefit comparisons of these different kinds of interventions. They show that deworming costs $3.50
per additional year of school participation, compared to $99 for the provision of free uniforms, and $36 for
nutritional supplementation. (the latter programme was targeted to pre-schools specifically)
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