Early childhood malaria prevention and ... - Wiley Online Library

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British Journal of Educational Psychology (2014), 84, 483–501 © 2014 The British Psychological Society www.wileyonlinelibrary.com

Early childhood malaria prevention and children’s patterns of school leaving in the Gambia Stephanie S. Zuilkowski1* and Matthew C. H. Jukes2 1 2

Florida State University, Tallahassee, Florida, USA Harvard Graduate School of Education, Cambridge, Massachusetts, USA Background. Early childhood malaria is often fatal, but its impact on the development and education of survivors has not received much attention. Malaria impacts cognitive development in a number of ways that may impact later educational participation. Aims. In this study, we examine the long-term educational effects of preventing early childhood malaria. Does intermittent preventive treatment (IPT) during early childhood reduce the risk of dropout? If so, does this effect vary by school type – government school versus madrassa? Sample. We use data from a 2001 follow-up of a 1985–1987 malaria prevention randomized controlled trial in the Gambia. The sample consists of 562 youth born between 1981 and 1986. Methods. We use discrete-time survival analysis to identify the impact of the intervention on dropout risk over time. Results. We find that IPT has a positive impact on dropout for government school students, but not for madrassa attendees. The difference was striking: in government schools, the odds of dropout in the treatment group were one third of those in the control group. Conclusions. Our findings suggest that preventing early childhood malaria may reduce dropout at a relatively low cost. In this intervention, the drugs cost less than one dollar per year per child. While IPT is no longer practised in many countries due to concerns over drug resistance, these results support the conclusion that any type of effective malaria control programme protecting young children, such as consistent and correct use of bed nets, could improve educational attainment in areas where malaria is prevalent.

In developing countries, children die each day from diseases such as cholera, measles, and malaria that are preventable or treatable with drugs that are widely available in wealthier countries. The focus of control efforts on preventing mortality from these diseases has diverted attention from the long-term impairments resulting from disease in early childhood. Children that survive their bouts with these diseases may suffer physical sequelae that impair their development and ability to live healthy lives, including attending school and completing cycles of education. In countries like the Gambia where universal enrolment is not the norm, children who are suffering cognitive impairments are likely to be among the most vulnerable to school dropout. An effective way to promote educational attainment in such areas is to control the diseases that impair cognitive

*Correspondence should be addressed to Stephanie S. Zuilkowski, Florida State University, University Center C4600, Tallahassee, FL 32306, USA (email: [email protected]). DOI:10.1111/bjep.12033

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Stephanie S. Zuilkowski and Matthew C. H. Jukes

abilities. In this study, we investigate the long-term educational effects of an early childhood malaria prophylaxis programme conducted in the Gambia from 1985 to 1987.

Background and context Malaria, a disease caused by Plasmodium species parasites and transmitted by mosquitoes, is among the most widespread diseases in the developing world. In 2010, there were an estimated 216 million cases around the world and 655,000 deaths (World Health Organization, 2011). Seventy-five per cent of the deaths are among African children (Breman, 2001). Infants and preschool-aged children are particularly at risk, as older children and adults living in malarial regions have generally developed some level of resistance. The seasonal variation in malaria transmission varies globally. Where malaria is endemic (present year-round), the population may develop a partial immunity to the parasites. In West Africa, malaria is epidemic, meaning that it is transmitted during and shortly after the rainy season. This results in fewer opportunities to develop immunity against more severe cases of malaria. Appropriate drug treatment is generally effective both preventively and after infection, despite the challenges of drug resistance. However, many of the two billion at risk do not have access to these drugs. Among school-age children, malaria is linked to absenteeism (Chuma, Okungu, & Molyneux, 2010; Leighton & Foster, 1993; Thuilliez et al., 2010; Trape et al., 1993). Evidence from randomized control trials is also accumulating that preventing and treating malaria among schoolchildren can improve cognitive abilities and educational achievement. In a cluster-randomized trial in western Kenya, Clarke et al. (2008) found that children treated preventively with sulfadoxine–pyrimethamine (SP or ‘Fansidar’) in combination with amodiaquine three times during a 12-month period had improved scores on two measures of sustained attention – code transmission and counting sounds. While Clarke et al. did not find any effect of treatment on educational achievement, as measured by a researcher-developed multiple-choice social studies test, in a randomized control trial in Sri Lanka, children who were preventively treated with chloroquine weekly between March and November 1999 performed 26% better on their schools’ term-end assessments in both language and mathematics (Fernando, de Silva, Carter, Mendis, & Wickremasinghe, 2006). In another analysis from their study, Fernando et al. found that even one bout of malaria was negatively associated with student performance on the language and mathematics tests (Fernando, de Silva, & Wickremasinghe, 2003). Despite this evidence, the cognitive and educational impact of malaria in early childhood is still poorly understood. The long-term effects of malaria could potentially be severe, impacting directly children’s cognitive abilities (Fernando, Rodrigo, & Rajapakse, 2010). Recent evidence from Uganda suggests that asymptotic malaria infection is related to lower sustained attention and abstract reasoning abilities among primary school-age children (Nankabirwa et al., 2013). Malaria causes anaemia, which can lead to cognitive impairment in young children (Jukes, Drake, & Bundy, 2008; Korenromp et al., 2004). In young children, anaemia has been shown to affect behaviour, making children less likely to explore their environment and subsequently affecting the behaviour of caregivers towards the children (Lozoff et al., 1987). Cerebral malaria, the most serious form, can lead to impaired cognitive development, acquired language disorders, and long-term neurological problems including epilepsy and cerebral palsy (Brewster, Kwiatkowski, & White, 1990; Carter et al., 2006; Idro et al., 2010; Kihara, Carter, & Newton, 2006; Mung’ala-Odera, Snow, & Newton, 2004).

Malaria prevention and dropout in the Gambia

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Thus, several potential pathways exist for the long-term impact of early childhood malaria on educational attainment. Evidence suggests that children’s early health and developmental experiences do indeed have lifelong impacts on their cognitive abilities, education, and behaviour. Birthweight has been linked to the number of years of schooling completed in Brazil, Guatemala, India, the Philippines, South Africa, and the United States (Behrman & Rosenzweig, 2004; Martorell et al., 2010; Victora et al., 2008). In Guatemala, women who received nutritional supplementation during early childhood completed 1.2 years more education than those who did not (Maluccio et al., 2009). Children with iron deficiency in the second year of life are more likely in adolescence to have poor motor, cognitive, and educational outcomes; anxiety and depression; and attentional, social, and behavioural problems (Lozoff, Jimenez, Hagen, Mollen, & Wolf, 2000). Recent follow-ups of long-term studies in Turkey (Kagitcibasi, Sunar, & Bekman, 2001; Kagitcibasi, Sunar, Bekman, Baydar, & Cemalcilar, 2009) and Jamaica (Walker, Chang, Vera-Hernandez, & Grantham-McGregor, 2011) have shown that early childhood enrichment and psychosocial stimulation are related to educational attainment later in life. For malaria itself, retrospective studies using data from the United States (Bleakley, 2010) and Paraguay and Sri Lanka (Lucas, 2010) provide some evidence that exposure to malaria in childhood has long-term effects on educational outcomes. In India, Cutler, Fung, Kremer, Singhal, and Vogl (2010) find limited evidence of an effect of malaria on women’s educational attainment, but not men’s. Looking across 125 countries, Thuilliez (2007) finds that countries with heavier malaria burdens have higher primary repetition rates and lower completion rates. The only prospective study to date, and the basis of the current analysis, showed (with a borderline statistical significance) that prevention of the disease in early childhood subsequently led to an increase in educational attainment of half a year of schooling (Jukes et al., 2006). What is lacking from this and other studies of the long-term impacts of a disease is an understanding of how the cognitive impairments they cause play out over children’s educational careers. Whether or not poor cognitive abilities in early childhood lead to poor educational outcomes depends on the interplay of several factors including the child and parent’s behavioural response to the developmental insult, the potential for cognitive stimulation in the child’s home, the perception of the child’s abilities in the eyes of their parents and teachers, the support provided for their education, and the cognitive demands placed on children at school. The current study aimed to probe two aspects of the effect of malaria infection on educational attainment. First, we are interested in identifying the grades at which the risk of malaria-related dropout is highest. Do children with poorer cognitive abilities find schooling challenging and quickly drop out in the first few grades, or is dropout more common in the latter stage of primary school, when achievement is emphasized in the run-up to primary school leaving examinations? Second, we examine how the treatment effect plays out in the two types of school children attended. Our hypothesis is that government primary schools placed different cognitive demands on children from Islamic madrassas and that the number of years of study in madrassas is determined by the goals of parents and madrassas rather than by student achievement. Before addressing these questions, we develop each of these hypotheses further.

Potential mechanisms connecting malaria and school dropout over time We hypothesize that the main mechanism for any observed effect on school persistence over time is long-term cognitive impairment among children not protected from malaria. As discussed above, malaria infection in young children can lead to cognitive impairment

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before school entry. The long-term implications for children’s persistence at school are hypothesized to be largely through their achievement. Children with poorer cognitive skills as they enter school perform less well in class and become more likely to drop out in the subsequent years (Liddell & Rae, 2001). This dropout is the result of a complex interaction between children’s achievement and the perception of their prospects in school by themselves, their teachers, and their parents. Families’ decisions on dropout in developing countries like the Gambia are multifaceted, balancing the direct and indirect costs of education, family resources, the child’s abilities and interest, and cultural norms around education (Piper, Jukes, & Miguel, in preparation). As students age and complete grades, the opportunity costs of remaining in school rise (Kingdon & Theopold, 2006). Opportunities for employment, and for girls, marriage and childbearing, offer an attractive alternative to school. At the same time, the incentives to stay in school decrease for those whose chances of passing the primary school examination become vanishingly small. It is likely that any early disadvantage in educational achievement due to malaria-related cognitive impairment will be compounded over time (Stanovich, 1986). On this basis, we would hypothesize that children affected by malaria in early childhood would lag further and further behind in educational achievement over time and become more likely to drop out in order to take advantage of opportunities outside school. Thus, we expect that the impact of early childhood malaria infection on dropout would be greatest at higher grades, particularly at government schools, where cognitive demands on students were likely higher. Given the long time frame covered in our analysis, however, the problem of effect fadeout must be considered. It is reasonable to expect that the programme’s cognitive effects would be stronger in the early grades of primary school, which are more proximal to the treatment than later grades.

Potential mechanisms connecting madrassa attendance and school dropout We next examine children’s attendance of the government primary school or the Islamic madrassas. Ninety per cent of Gambians are Muslim (CIA, 2008). Madrassas are considered by parents to be an alternative to government-run schools in many parts of West Africa, as they are in other Muslim areas of the world. In this sample, well over half of the students attended madrassas. In some countries, including in recent years in the Gambia, the subject specialties taught in madrassas may include all of those found in a government school. However, the children in our study attended a more common model of madrassa education following a limited course of study focused on memorizing the Koran and learning religious practices. Compared to madrassas in countries like Yemen and Saudi Arabia, which have drawn international attention for purported links to terror groups, little has been published on Gambian madrassas. However, given what is known about style of instruction in madrassas versus government schools, it is possible that malaria prophylaxis and any subsequent improvement in cognitive development would benefit students studying in government schools more than those studying the more limited curriculum of a typical madrassa. Two strands of research on Islamic madrassas are relevant to our research questions on school leaving. First, it is possible that madrassas are less cognitively demanding than government schools. In terms of educational attainment, any cognitive boost from malaria prevention is only relevant if schools require advanced cognitive skills. Evidence on madrassas from a variety of countries suggests that the pedagogical style used in most, particularly at the primary level, is not likely to require advanced critical thinking and reasoning abilities. Abd-El-Khalick, Boyle, and Pier (2006) note, in their report on Islamic


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education in Nigeria, that ‘despite the variation one finds from one country to another and even within countries, [Islamic schools] constitute a particular form of schooling, one with… a particular set of beliefs about education and learning, and distinctive pedagogical methods’ (p. 2). Madrassa education, especially in the early years, tends to focus on the memorization and recitation of the 60 chapters of the Koran (Bano, 2009; Colley, 2005). Boyle (2006), in her research on madrassas in Morocco, Yemen, and Nigeria, found that ‘knowing’ the Koran meant memorization of sections rather than being able to understand and explain the text. Abd-El-Khalick et al. report that ‘lower-level cognitive interactions that ask students to memorize, repeat, or recall information or content are predominant in the greater majority of the observed classrooms’ (2006, p. 8). Pedagogically, madrassa education is teacher-centred rather than student-centred (Malmberg, Mwaura, & Sylva, 2011; Park & Niyozov, 2008). Madrassa teachers are described as ‘harsh taskmasters who punish students severely’ (Bray, Clarke, & Stephens, 1986, p. 85) and as producing ‘affective conditions in the majority of the observed classrooms [that] were stressful or, at least, not favorable from the perspective of students’ (Abd-El-Khalick et al., 2006, p. 9). This educational environment is unlikely to result in optimal cognitive development among primary school students. Other analyses of this data set which are in progress support the hypothesis that there is a relationship between school type and cognitive development. At follow-up, participants with madrassa education performed more poorly than government school attendees on a battery of cognitive tests, which measured abilities shown to be affected by the malaria intervention. A second possible way in which the effects of malaria treatment would evolve differently by school type concerns the aims of madrassas and parents’ choice of school type. Madrassas have a different mission than government schools. The goal of primary-level madrassas (Koranic schools) is to enable children to read and recite the Koran, a task that can generally be accomplished in 3–4 years (Anzar, 2003). When Boyle, Seebaway, Lansah, and Boukamhi conducted focus groups on Islamic education in Ghana, 60% of the groups agreed that the ‘schools’ primary purpose is to help children understand and promote the Islamic religion’ (2007, p. 34). While these children may attain literacy through their studies, this type of education is not generally intended to prepare children to become doctors, lawyers, and government officials. Higher-level Islamic schools exist in many countries, but few exist in West Africa (Anzar, 2003). Furthermore, given that these participants were in primary school during the mid-to-late 1980s and 1990s, their odds of having had access to an advanced Islamic school are low. Therefore, one would expect rural Gambian children attending madrassas to stop attending after a few years, after accomplishing the goals of learning to recite the Koran and be observant Muslims, regardless of their level of cognitive ability. It is even possible that improved cognitive ability would lead to children completing the curriculum more quickly and leaving madrassas after a shorter period of time. There are a number of reasons, in addition to the desire for children to have a religious education, why parents might choose to send some or all of their children to madrassas even if a government school were available. In Nigeria, some parents saw the government schools as a legacy of colonialism and missionary movements and turned away from the government education system as a form of protest (Bano, 2009). Other parents may make their decisions about their children’s school type based on more practical concerns. Qualitative work by Okuma-Nystr€ om (2003) suggests that some parents send a few children to the government school, hoping that they will advance far enough to obtain well-paid employment in the city, while sending others to the madrassa so that they will learn to be good Muslims and community members. Okuma-Nystr€ om quotes several

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parents who state that children who go to madrassas are more tied to their communities, are willing to work in the fields alongside their families, and will remain in the local area to care for their parents. Given these varying aims for their children, this decision by parents, made when the children are very young, may mean that those sent to government schools are expected to stay in school as long as they are performing well in school, while those sent to madrassas may drop out earlier if the family needs them at home, regardless of their performance in school. Due to the cost and relatively long time commitment involved in putting children through the government school system, parents may also make their schooling decisions based on their perceptions of the child’s initial cognitive abilities, investing more in children who seem more capable of academic achievement.

Research questions The above analysis suggests that the impact of early childhood malaria on children’s chances of dropping out may be different in the latter years of schooling compared with the early years, and in government primary schools as compared with madrassas. We will investigate these patterns in our two central research questions. (1) Is the difference in school attainment between treatment and control group children greater among those who attend government schools as compared with those who attend Islamic madrassas? (2) Does the percentage of dropout attributable to malaria increase at later grades, as the cognitive demands of schooling increase?

Research design The data set that we analyse here originates from a controlled trial of an early childhood malaria prophylaxis programme conducted between 1985 and 1987 in the Gambia (Greenwood et al., 1988). Investigators drew participants from fifteen villages within a range of approximately 30 km from Farafenni on the north bank of the River Gambia. Two of the fifteen villages did not complete the study because the village health worker had either died or been dismissed, and three additional villages dropped out due to deficiencies in drug supply. Thus, 10 of the fifteen original villages completed the study, and we include participants from those villages in our analyses. Within each village, assignment to treatment and control groups was systematic; every other compound was selected into the treatment group. The study design included 6 birth-year cohorts of participants. The first cohort of children, born in 1981, received treatment during the malaria transmission seasons of 2 consecutive years, 1985 and 1986. The second cohort – comprised of those born between 1982 and 1985 – received 3 years of treatment from 1985 to 1987. The third cohort – comprised of children born in 1986 – received 2 years of treatment in 1986 and 1987. However, children may have received less treatment than indicated by their cohort membership if they moved from the village during the study period or if they failed to take prophylaxis as requested. Our treatment predictor therefore represents an intent-to-treat rather than treatment itself. In addition to the treatment provided during the controlled trial, all members of the cohorts born in 1983 and later were eligible for a post-trial prophylaxis programme administered by the Gambian government. This mass treatment was implemented as a consequence of the initial findings of the study – that treatment reduced deaths among children by 40% and malaria-related deaths by 80% (Greenwood et al., 1988; Jukes et al., 2006). Beginning in 1988, the government-run prophylaxis


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programme lasted for at least 2 years in these villages before being replaced by an insecticide-treated bed net (ITN) programme (Allen, Snow, Menon, & Greenwood, 1990). In 2001, researchers conducting a follow-up study located 579 (49%) of the participants from the former controlled trial and gathered information on their educational attainment and cognitive functioning. The data set we analyse here includes the 562 participants whose follow-up data provided information on the highest school grade they completed by the time of data collection. In Tables 1 and 2, we compare descriptive statistics on treatment and control group members at follow-up. There were no statistically significant differences between the treatment and control group members at follow-up on gender, age, or madrassa attendance. The years of treatment for those in the treatment group differed by cohort, as noted above; the median years of treatment was two. All children enrolled in school, but overall grade attainment was low. As shown in Table 2, relatively few students had reached secondary school. Girls were at a particular disadvantage. Two thirds of girls in the sample had completed third grade or less. Over 70% of boys in the sample had completed fourth grade or higher.

Procedures Children in the treatment group were administered an oral dose of Maloprim (dapsone/ pyrimethamine) by a village health worker every 2 weeks during malaria transmission season; control children were administered a matching placebo pill. The study was double-blind – neither the field staff nor the participants knew the group assignments. Compliance in the final year of the study was 60% in the placebo group and 59% in the treatment group, indicating that the drug or placebo was given as intended in 6 of 10 person-administration instances. Despite this low level of compliance, children who received Maloprim were less likely to have died from malaria during the original study, indicating that compliance was sufficiently high to affect children’s health outcomes (Greenwood et al., 1988).

Measures We have organized the data in a person-period data set. Individual participants contributed differing numbers of rows to the data set, corresponding to the number of grades of school they had completed by the time they left school or by the date of data collection, whichever came first. In each row, we record the values of the outcome and predictors, as follows: Table 1. Comparison of treatment and control groups at follow-up on selected demographic and treatment variables (n = 562) Variable Female Mean age Years of treatment during trial 0 1 2 3 Eligible for mass treatment Attended a madrassa

Treatment

Control

p

48% 17.0

49% 17.1

.745 .729

276 23 129 134 53% 63%

52% 63%

.815 .908

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Table 2. Highest grade completed by study participants attending government schools and madrassas as of 2001 School type Overall

Government

Madrassa

Grade

Frequency

%

Frequency

%

Frequency

%

0 1 2 3 4 5 6 7 8 9 10 11 12 Total

81 61 72 73 57 60 56 45 26 23 6 1 1 562

14.4 10.9 12.8 13.0 10.1 10.7 10.0 8.0 4.6 4.1 1.1 0.2 0.2

2 9 10 11 21 31 44 34 25 16 2 1 1 207

1.0 4.4 4.8 5.3 10.1 15.0 21.3 16.4 12.1 7.7 1.0 0.5 0.5

79 52 62 62 36 29 12 11 1 7 4 0 0 355

22.3 14.7 17.5 17.5 10.1 8.2 3.4 3.1 0.3 2.0 1.1 0 0

Outcome LGC: A dichotomous time-varying indicator of whether the child was still in school in this year. If the year represented in the row was the child’s last year of enrolment, the row contains a value of 1 to indicate the event of ‘leaving school’ has occurred. If it was not the child’s last year, the row contained a value of 0. Participants who reported that they were still in school at the time of follow-up are censored.

Question predictors GRADE: A discrete time-varying variable that records the grade to which the row of data refers, coded from 0 to 9. GRADE2: A discrete time-varying variable which is the quadratic expression of GRADE. TREATGRP is a time-invariant dichotomous variable that distinguishes members of the treatment group (coded 0 = control and 1 = treatment). MADRASSA is a time-invariant dichotomous predictor that indicates whether the child attended an Islamic madrassa rather than a government school (coded 0 = no and 1 = yes). Madrassa attendance and government school attendance were mutually exclusive in this sample.

Covariates MASSTREAT is a time-invariant dichotomous covariate that indicates whether the participant’s cohort was eligible for the government mass treatment programme (coded 0 = ineligible, 1 = eligible). FEMALE is a time-invariant dichotomous predictor that indicates whether the participant was a girl (coded 0 = male and 1 = female).


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VILLAGE is a vector of dichotomous predictors (V1–V10) to distinguish the 10 villages from which participants were drawn (each coded 0 = no and 1 = yes). We eliminated the predictor representing the tenth village from my analyses to create a reference category. We represent these covariates as a group by the symbol ‘Z’ in the hypothesized models that follow.

Data analytic plan We will address these research questions by fitting a taxonomy of discrete-time hazard models using logistic regression analysis in the person-period data set (Singer & Willett, 2003). As a baseline model for comparison, we propose to fit the following hypothesized discrete-time survival analysis model: Logit hazard LGCij ¼ b0 þ b1 GRADEij þ b2 GRADEij2 þ b3 TREATGRPi þ b4 Zi ;

ð1Þ

where we have represented the baseline logit hazard of event occurrence as a quadratic function of grade in school. The subscript i refers to the individual, while the subscript j refers to a specific grade for variables that vary by grade; Model 1 above therefore predicts individual i’s value of logit hazard in grade j. To address our research questions specifically, we will fit the following discretetime survival analysis model: Logit hazard LGCij ¼b0 þ b1 GRADEij þ b2 GRADEij2 þ b3 TREATGRPi þ b4 MADRASSAi þ b5 TREATGRPi MADRASSAi þ b6 Zi :

ð2Þ

Results Overall, risk of school leaving was highest for children who had just completed third grade – 16% of children left school at that point. In addition, there was also a spike in school leaving after the completion of upper basic school with grade nine, corresponding to the transition to senior secondary school. As demand for secondary-school places exceeded (and still exceeds) supply, many students are forced out of school after ninth grade. The median grade completion for students in the sample is approximately 4.5 years. Of this sample of ever-enrolled young people, only 30% survived past the end of ninth grade. In Figures 1 and 2, we present the conditional probabilities of leaving school and the survival probabilities, respectively, as functions of grade completed. When comparing the hazard and survival functions by school type, divergent patterns emerge. For children attending madrassas, the periods of highest risk of school leaving were after third, fifth, and sixth grades. After each of these grades, over 30% of students left school. Risk of school leaving was low overall for government school students until the completion of ninth grade, at which point 20% of students left. As shown in Figure 2, the median grade achievement for a madrassa student was approximately 2.5 years. In contrast, so many government school students were still enrolled at follow-up that the median grade achievement was not reached by the end of ninth grade. These descriptive findings underline the importance of including school type in the analyses.

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Stephanie S. Zuilkowski and Matthew C. H. Jukes 0.35

Government school Madrassa

Esmated hazard probability

0.3 0.25 0.2 0.15 0.1 0.05 0 0

1

2

3

4

5 Grade

6

7

8

9

10

Figure 1. Hazard of leaving school after completing grades, by school type. 1

Government school Madrassa

Esmated survival probability

0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0

1

2

3

4

5 Grade

6

7

8

9

10

Figure 2. Sample survivor function, by school type. Research question one: Do children who attend government schools benefit more from malaria prevention, in terms of highest grade completed, than children who attend Islamic madrassas?

To address our first research question, we investigated how treatment affected children in madrassas and government schools, respectively. Model 1 includes variables for the effects of grade, gender, and treatment as well as relevant interaction terms (Table 3). In Model 2, we introduce variables indicating school type as well as statistical interactions between school type, grade, and treatment group. The results of these models show that the enrolment patterns of children attending madrassas and government school students are strikingly different. Among children attending


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Table 3. Fitted discrete-time hazard models predicting risk of leaving school, by grade, preventive treatment, and school type (n = 562) Model 1 GRADE GRADE2 FEMALE GRADE 9 FEMALE GRADE2 9 FEMALE TREATGRP MASSTREAT MADRASSA TREATGRP 9 MADRASSA GRADE 9 MADRASSA GRADE2 9 MADRASSA _cons ll df_m

0.094 (.129) 0.008 (.016) 0.761** (.282) 0.680*** (.187) 0.108*** (.027) 0.386** (.145) 0.517*** (.136)

2.807*** (.399) 831.9 16

Model 2 0.013 (.237) 0.040 (.025) 0.370 (.294) 0.552** (.192) 0.079** (.026) 1.055** (.341) 0.323* (.140) 1.785*** (.531) 0.718 (.372) 0.388 (.259) 0.070* (.030) 4.518*** (.601) 750.3 20

Note. These models include the fixed effects of village. Standard errors in parentheses. *p < .05; **p < .01; ***p < .001.

government schools, treatment group children, in any grade, had about one third the odds of a control group member of leaving school after completing that grade (OR = 0.35, p = .0024). The coefficient on the TREATGRP 9 MADRASSA interaction indicates that the school-leaving patterns between treatment and control groups differed by the type of school attended (b5 = .718, p = .054). This model suggests that among madrassa attendees, treatment group children in any grade had about 0.7 times the odds of a control group member of leaving school after completing that grade, although this difference is not statistically significant. In interpreting these results, we note first that the observed differences in treatment-related dropout patterns between government schools and madrassas were substantial and striking. This is an empirical finding which calls for explanation. We identify three possible explanations for these observed effects: differences in apparent effect sizes between government schools and madrassas could be due to (1) the differing natures of the school types and the demands they place upon students, (2) differential sorting of children into school types as a result of the intervention, or (3) differences between the type of children who attend madrassas and government schools. We will discuss each of these possible explanations in turn below. We argue that the likeliest explanation for the differential treatment effects is that cognitive ability was a more important determinant of educational attainment in government schools than in madrassas. This position is supported by the literature discussed above, which suggests that primary-level madrassas focus on memorization and repetition rather than on critical thinking skills and analysis. To investigate this explanation, we used a measure of cognitive ability collected at the endpoint of the study. The measure is the principle component derived from analysis of performance on six cognitive tests (Jukes et al., 2006). We find that students who attended government schools had higher cognitive ability scores than those who attended madrassas. Controlling for gender and socioeconomic status, youth who attended government schools scored on average 0.7 standard deviations higher than madrassa attendees

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(p < .001). This is evidence either that more able children attend government schools or that they become more able as a result of attending these schools. Figure 3 shows that years of schooling is positively related to cognitive ability for government school students, but not for madrassa students (bgov = 1.36, p < .001; bmadrassa = .02, p = .891). This is evidence either that spending more time at government schools improves children’s cognitive ability or that higher cognitive ability enables children to reach higher levels of educational attainment in government schools. Both interpretations support our hypothesis that government schools placed heavier cognitive demands on students than did madrassas. A second explanation of our findings is that they result from sorting into school types on the basis of parents’ perception of children’s cognitive abilities. An earlier analysis of this data found that, among children who were in the trial for longer, the malaria intervention improved cognitive ability in the treatment group, as measured by digit span, categorical fluency, visual search, Raven’s Colored Progressive Matrices, the Mill Hill Vocabulary Test, and a proverb test similar to a subtest of the Wechsler Adult Intelligence Scale (Jukes et al., 2006). Given these earlier findings, it is possible that the intervention affected the types of schools children attended. We fit a post-hoc model for choice of school type to investigate this explanation. As Model 4 in Table 4 shows, the intervention does not appear to have influenced school choice among treatment group members, confirming earlier findings using this data (Jukes et al., 2006). The analysis estimated that odds of attending government school were reduced by only 10% in the treatment group. However, the standard error on this estimate (.246) leaves open the possibility that treatment had an effect on school choice. There may also have been sorting on the basis of unobserved attributes. The third potential explanation is that the differential treatment effect was due to differences in the children who attended madrassas and government schools, rather than to the differences between the school types themselves. For example, our data show that government school enrolment was higher among boys than among girls. However, we did not find any interaction between treatment and either gender or tribe which one

2

Cognitive performance

1.5

Government Madrassa

1 0.5 0 –0.5

1

2

3

4

5

6

7

8

9

10

–1 –1.5 –2 –2.5

Last grade completed

Figure 3. Mean cognitive assessment factor scores for youth leaving school after completing given primary grades, by school type.


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Table 4. Odds ratios associated with attending a government school (n = 562)

FEMALE TREATGRP MASSTREAT _cons ll df_m

Model 3

Model 4

1.703*** (.251)

1.968*** (.291) 0.101 (.246) 0.655** (.224) 1.126* (.574) 289.5 12

0.793 (.533) 293.9 10

Note. These models also include the fixed effects of village. Standard errors in parentheses. *p < .05; **p < .01; ***p < .001.

would expect if child characteristics, rather than school characteristics, were responsible for the treatment effect.

Research question two: Does the percentage of dropout attributable to malaria increase at later grades? To answer our second question, we now examine the patterns of school leaving across the grades included in this analysis. The overall estimated odds of leaving government schools is reduced by 65% in the treatment group as compared to the control group (OR = 0.35). We find no evidence that this odds ratio varies with school grade. However, the overall odds of school dropout do vary by grade. This is evident in Figure 4, in which we illustrate the differing risks of school leaving over the first nine grades by plotting the fitted hazard functions for experimental and treatment group students in government schools and madrassas. As can be seen in Figure 4, the risk of government school students leaving is low in the early years. However, a treatment effect is still visible. After completing first grade, the risk of school leaving is twice as high for control group children (2%) than for 0.4

Control-Government Control-Madrassa

Treatment-Government Treatment-Madrassa

0.35

Fitted hazard

0.3 0.25 0.2 0.15 0.1 0.05 0 0

1

2

3

4 5 6 7 Highest grade completed

8

9

10

Figure 4. Fitted hazard function for school leaving, by school type and experimental group.

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treatment group children (1%). After fifth grade, the differential in dropout risk has increased – only 2% of treatment group government school students will leave after completing grade 5, compared to 3% of control group students. After ninth grade, the risk of control group students leaving government schools remains nearly three times as high as the risk for treatment group students (19% vs. 7%). In madrassas, risk of school leaving is higher overall than in government schools and the risk differential between treatment and control group students is smaller and not statistically significant. However, differentials favouring treatment group members are still observed. For example, in fifth grade, risk of leaving school is 28% for treatment group students and 35% for control group students attending madrassas. Across the first nine grades, this difference in risk results in poorer outcomes for control group students in terms of average grade completion.

Discussion In summary, these findings strongly suggest that preventing malaria in early childhood may protect against school dropout in the Gambia. In our first analysis, we found an overall protective effect across the sample, with an odds ratio of .68 (p = .008), independent of the type of school students attended. When factoring school type into the analysis, we cannot unambiguously differentiate among the hypotheses presented above. Given our sample size and the limited baseline data available to us, we cannot powerfully reject null hypotheses. Notwithstanding the limitations in drawing causal inferences, we argue that the descriptive patterns presented in our data are striking and call for explanation. The odds of government-school-attending treatment group members leaving school after any given grade were one third the risk of control group students. Overall, this pattern is consistent with our hypotheses that the children who attend government schools would benefit more from malaria prevention than children who attend Islamic madrassas. This programme’s success in reducing school leaving years after the end of the actual malaria treatment is particularly interesting because the treatment was not designed to have an educational impact. Additionally, we did not find a statistically significant interaction between treatment and grade during the model-fitting process, indicating that the treatment was consistently effective, in terms of odds ratios of school leaving, across the grades analysed here. The reductions in risk of school leaving associated with malaria treatment are quite large. Focused efforts to prevent dropout are in place in many developing countries; if any of these initiatives were able to produce this level of change, they would be declared major successes. Even though this was not designed as an educational intervention, this impact of malaria prevention on school leaving provides support to the position that health and educational interventions, particularly those aimed at young children, may be synergistic. Our hypothesis was that the differential treatment effect resulted from the nature of the two types of school children attended. While we cannot definitively rule out alternative explanations, we argue that our data are more consistent with the first explanation presented above – that when other factors are held constant, the cognitive benefits of early childhood malaria prevention are more likely to lead to improved educational attainment in government schools as compared with madrassas. Two potential pathways drawn from the literature discussed represent plausible versions of this explanation. It is possible that the pedagogic style of the madrassas the children in this study attended did not require advanced cognitive skills, and thus, the protective effects of


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early childhood malaria treatment were not particularly advantageous for students attending them. In contrast, the second explanation is that students are expected to attend madrassas for a fixed period of time, determined by the goals of parents and the madrassas themselves, but not by student cognitive achievement. Our analyses support these two explanations – although cannot distinguish between them – in that they point unambiguously to a relationship between cognitive abilities and educational attainment for government school students, but not for those attending madrassas. The participants involved in this study attended primary school – government or madrassa – in the mid-to-late 1980s and early 1990s. However, the conclusions of this study are still relevant today. First, despite an agreement between the government and the general secretariat for Islamic/Arabic education to align the syllabi of government and religious schools at the primary level, the limited evidence available on madrassa curricula in the Gambia suggests that these schools remain quite different from government schools. One study finds that on average, the curriculum in Gambian madrassas spends more student–teacher contact hours on Islamic education than on the official languages, science, or math. In fact, Islamic education and Arabic instruction totalled almost half of the weekly contact time in primary-level madrassas (Moussa & Benett, 2007). Therefore, our assumption that children attending government schools and madrassas use differing degrees of cognitive skills remains reasonable. Second, the dropout pattern we observed persists in the Gambia, according to the most recent estimates available. In 2010, the gross enrolment rate was 83% for primary school, but just 54% for secondary school. School life expectancy was just 8.3 years (UNESCO Institute for Statistics, 2013). These data confirm that dropout continues to be a problem in the Gambia, despite the Education for All movement. Our findings have relevance to education in many countries around the world where malaria is prevalent and particularly in West African countries where madrassas are common alternatives to government schools. However, we would expect early childhood malaria prevention programmes to differ in their effect on education according to a number of contextual factors. First, the impacts of early childhood malaria prevention efforts on cognitive development depend on the prevalence and severity of malaria. This depends, in turn, on the seasonality of malaria, levels of acquired immunity, bed net use, and many other epidemiological factors. Second, the translation of disease into cognitive impairment is moderated by many factors including the presence of other nutritional and health conditions, cognitive stimulation provided at home and in programmes, and parental education (Bundy, Kremer, Bleakley, Jukes, & Miguel, 2009; Jukes et al., 2008). Third, the impact on educational attainment is likely to depend on basal levels of attainment in the country targeted. Educational access in the Gambia has improved somewhat, particularly for girls, since the time the participants in this study entered primary school. We would predict that small improvements in cognitive abilities would have a bigger impact in weak education systems where children’s attendance at school is precarious. Regions with higher levels of attainment may show less improvement with malaria prevention efforts. Finally, the cognitive and educational impact of malaria prevention may also vary with the prevention method used. Sustained chemoprophylaxis, as used in the current study, is no longer recommended as a means to control malaria because of concerns about drug resistance. Instead, control efforts now focus on intermittent drug therapy – either as prevention (intermittent preventive treatment, IPT) or targeted at infected children (intermittent screening and treatment) – bed net use, or indoor residual spraying. While intermittent screening and testing is necessarily more expensive per child than IPT due to the costs involved with testing, recent studies have

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shown such programmes to be affordable. In Kenya, Drake et al. (2011) calculated the cost per child screened to be $6.61, and note that changes in programme design may be able to reduce this figure by 40%. The cognitive impact of these control strategies has not been evaluated in early childhood, but is likely to be linked to the coverage and duration of protection offered by each method.

Limitations of the study and data set Researchers conducting the follow-up study found only 49% of the original study’s participants. We cannot determine in which direction this selection biases the results. Our estimates of the effects of treatment could be downwardly biased if treatment group students had a greater probability of leaving the area to attend a boarding school or seek more advanced educational opportunities. Conversely, our results could be upwardly biased if some of the treatment group participants who were lost at the follow-up died at a young age and due to illness completed fewer years of school than other children in their cohort. However, in 2001, the demographics were similar across the treatment and control arms of the study, as were the percentages of each group located (Jukes et al., 2006), suggesting that the treatment effect was not merely the result of differential follow-up rates. An additional limitation of these analyses is the fact that the effect of the intervention cannot be completely separated from the effect of the post-trial prophylaxis. Due to the structure of the study, the number of years of treatment a child received is associated with likelihood of eligibility for post-trial treatment. However, we assume that the post-trial mass treatment programme would bias our findings towards zero rather than causing an inflated estimate. Due to the limitations of the data set, we have measured time in our analyses using GRADE. However, it must be noted that highest grade completed, although policy relevant, does not measure how long it takes for a student to complete that level. We cannot differentiate between a student who takes 6 years to reach grade six and a student who takes 9 years to reach grade six. These differences carry important consequences at both the individual and system levels, but we cannot investigate them within this data set.

Conclusion Keeping children enrolled through primary school is a challenge with which many developing countries continue to struggle. Poverty, supply constraints, and ethnic, gender, and racial biases are only a few of the complex problems that must be dealt with in order to meet Education for All goals. However, this study suggests that preventing common health problems that affect cognitive development, like malaria, may reduce primary dropout at a relatively low cost; in this intervention, the drugs cost less than one dollar per year per child and were administered through the government community health worker system (Greenwood et al., 1988). Our results suggest that malaria control efforts among young children, such as consistent and correct use of ITNs, could improve educational attainment in areas where malaria is prevalent. While drug-based prevention of the type discussed here is no longer conducted on a wide scale due to fears of increasing drug resistance, these results are also be supportive of other methods of malaria prevention. Intermittent screening and treatment is a more current version of this intervention. In addition, a wide range of national governments, international organizations, and non-governmental organizations are working to expand


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the use of ITNs for all children and pregnant women. Our results suggest that the children could experience the benefits of these interventions throughout their educational careers and beyond.

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