Do longer classroom hours equal good grades? Spending more time in school is a subject currently being discussed as one solution to improving students' academic performance with the ultimate goal of making countries more competitive in the global economy.
This is true for emerging and advanced economies alike.
In the US, President Obama has called for more time in school, arguing that American students spend on average one month less in class than their South Korean counterparts. If American children are to compete with school students from a top Tiger economy  in the 21st century -the argument goes- then surely they cannot afford to start off at such a disadvantage.
But does more time in school really equate to better learning outcomes? It's a question that Latin American leaders are asking both themselves and us at the Bank.
Policies aiming to lengthen the school day have increased in popularity during the last decades. The rationale is simple: more time in class should translate into better learning, and longer school days for children can mean more time for parents to work.
For older kids, it can also have a "protective" effect, reducing their exposure to risks outside of school such as delinquency, substance abuse and crime and violence. The policy is attractive to decision makers in Latin America & Caribbean , where school days have traditionally lasted between four and five hours with both a morning and afternoon session. Falling birth rates, however, reduce demand for school places. This then opens the way for single-shift schools and the possibility of longer school days, by optimizing physical and human resources.
More time = more learning?
At first glance, the cross-country relationship between instructional time (as stated in the curriculum) and student learning (reading scores from PISA ) seems very weak (Figure 1). Although South Korea does score high in time and learning, other countries, like Italy and Mexico, have even more teaching hours, and far worse learning outcomes. The story in Latin America is almost identical (Figure 2).
Figure 1: Relationship between Annual Hours of Instruction & PISA Reading Results – Global Sample
Figure 2: Relationship between Annual Hours of Instruction & SERCE Reading Results – LAC Sample
Research measuring the impact of extended school days is limited. Eight studies across four Latin American countries –Argentina (Buenos Aires), Brazil (São Paulo), Chile, and Uruguay– demonstrated a pattern of positive results on student test scores. All six studies that measured student performance found at least some positive impacts. The other two studies found that extending the school day increased female labor force participation and reduced adolescent motherhood.
The magnitude of the impacts are mixed: In Uruguay, Full-Time Schools  (FTS) have shown a very positive impact on student learning, where on average students attending FTS perform much higher on standardized tests than their traditional school peers (about 0.26 and 0.38 of a standard deviation in language and math respectively over six years).
However, in São Paulo, a similar study showed strong effects in reading (0.13 standard deviation), but no effects in math.
The difference may be found in how schools choose to use the extra time. Many schools systems use the time to introduce extracurricular activities such as English, Information and Communication technologies (ICT), and culture, while others focus more on the core curriculum (reading and math). Some use the extra time to double up efforts to support struggling students, suggesting that longer school days can help close the gap in highly unequal schools systems. Indeed, some studies show that the greatest academic gains are realized in schools serving the poorest and most disadvantaged.
We do know that the educational benefits do not result automatically from lengthening the school day. These policies require careful design beyond just adding more hours to the timetable. An effective policy should consider the following elements:
· Scope: Will efforts be focused on specific population groups, schools or grades? Will the extension be universal or targeted?
· Scale: Will implementation be piloted, rolled out gradually or in one fell swoop?
· Prioritization: How will schools be selected?
· Length: By how many hours will the school day be extended? Which days of the week?
· Approach: Will the pedagogical/curricular approach be adjusted for the extended day, as in Uruguay?
· Allocation: How will the extra time be allocated? What will the breakdown be between core curriculum activities, and extra-curricular activities? What about school meals and breaks?
· Costs: What is the initial cost? What will the annual operational costs be? How will financial resources be assigned? From which funding sources?
· Stakeholders: How will stakeholders be involved and consulted, including students, parents, teachers, and school administrators? Despite concessions on extending the school day in Chicago, Mayor Rahm Emanuel was unable to avoid a teachers' strike . (Ironically, teachers in Peru are currently striking in favor of full-day school with an accompanying increase in salary, among other demands).
· Teachers: How should teachers be involved, trained and supported? How can schools be provided with the required human resources for the extended day?
In Latin America and the Caribbean we've been working closely with a number of countries as diverse as Brazil, El Salvador, the Dominican Republic, and Uruguay to explore some of these questions, through both financial and technical assistance.
The World Bank Latin America education team is preparing a report to support countries in defining effective extended school day policies and models. This study will deliver neither a one-size-fits-all formula nor a definitive sanction.
Rather, we aim to summarize lessons that can be synthesized from a critical review of the evidence and select case studies, identifying key factors taken from the successful experiences.
While the primary audience is the region's policymakers, we expect the findings to be of interest to many countries –perhaps even to those American kids that President Obama hopes will be able to better compete with their Korean counterparts.
Stay tuned, and send us your thoughts on these questions.
(With contributions by David Evans, Pablo Alfaro and Diego Ambasz)
- Nicaragua 
- Mexico 
- Jamaica 
- Honduras 
- Haiti 
- El Salvador 
- Ecuador 
- Dominican Republic 
- Colombia 
- Chile 
- Brazil 
- Bolivia 
- Argentina 
- Uruguay 
- Peru 
- Paraguay 
- Panama 
- Latin America & Caribbean 
- Education 
- schools 
- learning 
- Development 
- children