Study Finds Extended School Days Linked to Fewer Male Homicides in Dominican Republic

A longer school day is usually discussed as an education policy: more classroom time, more opportunities for instruction and more time for schools to provide supervision, meals, activities and support. In the Dominican Republic, however, researchers have asked a broader question: can keeping secondary-school students in school for more hours also affect serious crime?

A 2026 study by Santiago Garganta, Arnoldo López-Marmolejo, María Florencia Pinto and Joaquín Zentner provides one of the most detailed attempts to answer that question in the Dominican context. Published in the International Journal of Educational Development, the study examines the Jornada Escolar Extendida (JEE), or Extended School Day program, which expanded the length of the public-school day from about four hours to eight hours.

The central result is more nuanced than a simple claim that education reduces crime. The researchers find no statistically significant effect on aggregate crime when crime is measured using municipal homicide and car-theft rates. But when the data are broken down by victim characteristics and the timing of offenses, statistically significant patterns emerge: male homicides fall after the adoption of the JEE, and homicides occurring outside school hours also decline.

At the same time, the study finds no significant reduction in total car thefts and reports a statistically significant increase in car thefts occurring outside school hours. That distinction matters. The evidence does not show that the extended school day produced a general decline in criminal activity. Instead, it points to a more specific relationship between the policy and certain forms and timings of serious violence.

What the Dominican Republic’s Extended School Day Program Changed

The JEE was introduced as a major reform of the Dominican public-school system. Its purpose was not primarily to fight crime. The policy was designed to improve educational quality while strengthening schools as spaces of social protection for children and young people, particularly in vulnerable communities.

The Ministry of Education of the Dominican Republic, known as MINERD, describes the extended-school model as an eight-hour school day with additional time for educational activities, workshops, cultural programs, tutoring and other forms of student development. The policy was formally established as a national policy through Ordinance 01-2014. MINERD’s documentation describes the model as a full-day educational structure intended to improve learning while providing a broader and more protective school environment.

The program began on a pilot basis before expanding across the public education system. MINERD has reported that the model was initially introduced to a small number of schools and students and subsequently expanded to hundreds of thousands of students. More recent ministry figures show that the program has continued to grow substantially, although the scale of the system today is not the same as the period examined by the crime study.

That historical distinction is important. The study does not evaluate every aspect of the contemporary Dominican education system. Its empirical analysis focuses on the staggered introduction of the JEE and crime outcomes during the 2009–2019 period. The research therefore provides evidence about the effects associated with the policy’s rollout during that period, rather than a measurement of current crime conditions.

How the Researchers Tested the Policy

The main methodological challenge was determining whether changes in crime were actually associated with the extended school day rather than with other differences between municipalities.

Schools did not all adopt the JEE simultaneously. The reform was introduced progressively across geographic areas and over time. That variation allowed the researchers to compare municipalities before and after the program’s adoption while also accounting for differences between municipalities and changes affecting the country over time.

The researchers combined administrative information from MINERD showing when schools adopted the JEE with municipal-level crime data from the Oficina Nacional de Estadística (ONE), the Dominican Republic’s National Statistics Office. The crime data covered homicides and car thefts for municipalities from 2009 through 2019.

The study uses a two-way fixed-effects model with municipality and year fixed effects. In practical terms, the approach is designed to account for persistent differences between municipalities and for nationwide changes that affect municipalities in a given year. The researchers then estimate whether crime outcomes changed when the extended school-day program was introduced.

This design is important because a simple comparison between municipalities with extended schools and municipalities without them could be misleading. Municipalities selected for earlier implementation might differ systematically in poverty, education, urbanization, public investment, crime patterns or other characteristics. If those differences were ignored, an apparent relationship between schooling and crime could reflect pre-existing conditions rather than the policy itself.

The staggered rollout provides a stronger basis for identifying the policy’s effect. Even so, the findings should be understood within the limits of the study’s observational policy setting and statistical design. The research estimates the effect associated with the JEE rollout; it does not demonstrate that every component of the education reform independently caused the observed changes.

Why the Researchers Looked Beyond the Overall Crime Rate

The study’s most important analytical decision was not to treat crime as a single undifferentiated outcome.

Homicide and vehicle theft are very different offenses. They involve different motivations, opportunities and potential offenders. A policy could plausibly affect one without affecting the other. The timing of an offense also matters. If keeping students in school simply prevents them from being on the street during school hours, an effect should be concentrated during those hours. If the policy changes behavior, educational prospects or attitudes toward risk, the effects could continue after students leave school.

The researchers therefore examined both the type of crime and when it occurred. They also separated homicide outcomes by the sex of the victim.

This matters particularly in the Dominican Republic because official homicide statistics show a pronounced gender difference. ONE reported that men accounted for the large majority of homicide victims during the period surrounding the study. In its analysis of intentional homicide rates, ONE reported a 2018 rate of 17.86 per 100,000 for men compared with 2.96 per 100,000 for women, for a total rate of 10.40 per 100,000.

Those official figures provide context for why a male-homicide result can be statistically important without implying a comparable effect on all homicide victims. The study’s finding is specifically about the subgroup in which a significant change was detected.

The Main Finding: No Overall Reduction in Crime

The broadest result is also the easiest to misinterpret.

The researchers do not find a statistically significant reduction in aggregate crime. Their overall crime measures combine municipal rates of homicide and car theft, and the estimated effect of introducing the JEE is not statistically different from zero at that aggregate level.

This means it would be inaccurate to report the study as evidence that longer school days caused a general decline in crime in the Dominican Republic.

The distinction between a statistically significant result and a non-significant result is central here. A statistically significant estimate provides evidence that the observed association is unlikely to be explained by sampling variation under the model’s assumptions. A non-significant estimate does not prove that an effect is exactly zero, but it means the study does not provide sufficiently strong statistical evidence to conclude that the policy changed that outcome.

For readers trying to understand the practical significance of the research, the message is therefore not that schools became a comprehensive crime-prevention program. Instead, the evidence suggests that the policy’s effects were concentrated in particular categories of severe violence and particular periods of the day.

Male Homicides Declined After JEE Adoption

One of the study’s statistically significant findings is a reduction in the number of male homicide victims following adoption of the extended school-day program.

The researchers find no corresponding gender-specific pattern for car thefts. The result is therefore specific to homicide rather than evidence of a broad reduction in all forms of criminal behavior involving males.

The gender finding is especially relevant because homicide in the Dominican Republic, as in many countries, is heavily concentrated among men. ONE’s official homicide statistics show that male victims substantially outnumber female victims. The study’s result is therefore consistent with a change in an important component of the country’s violent-crime burden, while still falling short of demonstrating a reduction in crime as a whole.

The authors interpret the result alongside the timing of homicides. Their analysis finds that the decline is concentrated in homicides occurring outside school hours, while they find no comparable reduction during school hours.

Why the Timing of Homicides Matters

The timing result is one of the most informative parts of the study because it helps distinguish between possible explanations.

If the extended school day worked primarily through a simple supervision mechanism, researchers would expect crime to fall mainly while students were physically in school. The logic is straightforward: students who would otherwise be outside are spending those hours under adult supervision and therefore have fewer opportunities to participate in certain risky activities.

The researchers call this the incapacitation channel. It does not mean incapacitation in the criminal-justice sense. In this context, it means reducing opportunities for certain behavior by changing where young people spend their time.

But the study finds no significant reduction in homicides during school hours. Instead, the significant reduction occurs outside those hours.

That pattern is difficult to explain through simple time substitution alone. The authors argue that it is more consistent with mechanisms that can affect behavior beyond the school day, particularly human-capital effects and changes in behavior toward risk.

The human-capital explanation is that more time in education can improve skills, educational attainment or future economic opportunities, potentially increasing the opportunity cost of criminal activity. A student who expects greater returns from education and legal employment may have more to lose from involvement in serious crime.

The behavioral explanation is different but related. A longer school day can provide a more stable environment, greater contact with supportive adults and less exposure to stressful or risky environments outside school. Over time, those experiences could influence behavior beyond the hours spent in the classroom.

These are interpretations of the observed pattern, not direct measurements of the psychological mechanisms themselves. The study does not establish that improved human capital or altered attitudes toward risk were individually responsible for the decline. Rather, the timing and subgroup results are more compatible with those channels than with a purely mechanical supervision effect.

The Concentration Effect: Why More School Time Could Also Increase Violence

The researchers also consider a potentially opposing mechanism: the concentration effect.

Keeping adolescents together for longer can increase supervision, but it can also increase interaction among young people who may be prone to conflict. Earlier research cited by the authors has found that school attendance can have different effects on different categories of juvenile crime, including circumstances in which more time in school reduces property crime while increasing some forms of violent behavior.

This creates an important theoretical tension. A longer school day can reduce opportunities for crime by keeping students supervised, while simultaneously increasing the amount of time adolescents spend interacting with one another.

The Dominican study does not find an overall increase in homicides attributable to this concentration mechanism. Instead, the significant homicide findings point toward reductions in male homicides and homicides outside school hours. That does not mean interpersonal conflict inside schools is impossible or irrelevant. It means the aggregate municipal homicide data do not show the kind of offsetting increase that would overturn the observed reductions.

Car Theft Tells a Different Story

The vehicle-theft results provide an important counterweight to the homicide findings.

The researchers find no statistically significant effect on total car thefts. That means the JEE cannot be described as a policy that reduced both violent and property crime.

But the timing analysis reveals something more unusual: car thefts increased significantly outside school hours, while the study finds no corresponding significant effect during school hours.

The authors interpret this as evidence of a possible temporal displacement of vehicle theft rather than an overall reduction. In other words, the policy may have changed when some car thefts occurred without reducing the total number of thefts.

This result is particularly useful for understanding why crime statistics should not be interpreted solely through aggregate totals. A policy can alter the timing or composition of crime even when the overall number of reported offenses does not change significantly.

It also reinforces the central caution of the study: the JEE was not a universal crime-reduction intervention. Its measurable effects differ by the type of offense being studied.

What the Official Data Say About Homicide in the Study Period

The study’s crime data cover a period in which the Dominican Republic was already experiencing a substantial decline in its homicide rate.

ONE’s statistical analysis reported that the national intentional-homicide rate fell from 11.98 per 100,000 people in 2016 to 11.96 in 2017 and 10.40 in 2018. The agency’s figures also show that men represented the majority of victims during those years.

The National Police has separately reported a longer downward trend in the intentional-homicide rate, citing a decline from 21.9 per 100,000 inhabitants in 2011 to 9.9 in 2019. These figures are useful for national context, but they should not be confused with the causal estimate in the JEE study.

The distinction is essential. A national homicide rate can fall for many reasons, including changes in policing, criminal markets, demographics, economic conditions, local violence patterns and other public policies. The fact that homicide was declining nationally during the period does not by itself demonstrate that the JEE caused any portion of that decline.

The study’s contribution is narrower and more specific: by exploiting the staggered rollout of the school reform across municipalities and controlling for municipality and year effects, it attempts to isolate the change associated with the adoption of the extended school day.

Why a Falling National Homicide Rate Does Not Prove the Education Policy Worked

This distinction between correlation and causation is particularly important in public-policy reporting.

Suppose homicide rates fall in the same years that more schools adopt an extended schedule. That temporal overlap alone would not establish that the school program caused the decline. The country could simultaneously experience changes in policing, employment, migration, demographics, drug markets, firearms availability or other factors affecting violence.

The study’s research design addresses part of this problem by using differences in the timing of JEE adoption between municipalities and fixed effects that account for persistent municipal characteristics and common year-level changes. This is substantially more informative than simply plotting the national education and homicide trends against one another.

Even so, the most responsible interpretation remains the one offered by the study itself: the JEE is associated with specific reductions in homicide outcomes, particularly male homicides and homicides outside school hours, while there is no evidence of a general reduction in aggregate crime.

What the Findings Mean for Dominican Education Policy

The results matter because the JEE was not designed as a narrow security program. It was an education reform whose potential social effects extend beyond academic performance.

MINERD has explicitly described extended schools as spaces that can provide social protection and additional opportunities for students. The model includes not only longer instructional time but also meals, tutoring, workshops, cultural activities and other programs. That broader environment makes it difficult to treat the number of hours alone as the entire intervention.

The study therefore raises a larger policy question: whether investments in education can generate benefits that are not captured by test scores or graduation indicators.

A 2024 Inter-American Development Bank study by members of the same broader research team examined the JEE’s relationship with learning outcomes among secondary students using national-test data from 2010–2019. That research found relatively low and unstable overall effects on test scores, while identifying changes in learning gaps between boys and girls in some assessments.

Read together, the education and crime research suggests that evaluating a long school day solely through classroom test scores may overlook other potential outcomes. At the same time, neither study supports the idea that simply adding hours automatically produces large improvements across every outcome.

The Results Do Not Mean Longer School Days Automatically Make Communities Safer

There are several reasons to avoid turning the study into a simple policy slogan.

First, the research concerns a specific Dominican reform implemented in a specific institutional and social context. Results from the Dominican Republic cannot automatically be transferred to another country with a different school system, labor market, crime pattern or level of violence.

Second, the study measures municipal crime outcomes rather than individual student behavior. The researchers can identify changes in homicide and vehicle-theft rates associated with the policy rollout, but the data do not establish that a particular student who spent more time in school was less likely to commit a crime.

Third, homicide is a relatively rare outcome compared with many other forms of crime. A significant effect on male homicide victims is important, but it should not be interpreted as evidence that the policy reduced assaults, robberies, burglaries, drug offenses or other crimes that were not part of the study’s main outcome measures.

Fourth, the study’s significant car-theft result points in the opposite direction from the homicide result when the timing of offenses is examined. That is another reason the evidence does not support a simple claim that more school automatically means less crime.

The Difference Between Reducing Certain Homicides and Reducing Crime Overall

For readers unfamiliar with how crime research is evaluated, this is perhaps the most important distinction in the paper.

The table illustrates why the headline cannot simply be “longer school days reduce crime.” The statistically significant findings are real and potentially important, but they are selective.

In statistical research, a null result is also information. The absence of a significant effect on total crime and total car thefts tells policymakers that the intervention did not produce a broad, detectable reduction across those outcomes within the study’s measurement framework.

What the Study Can and Cannot Establish About Causality

The researchers explicitly frame their analysis as an attempt to estimate a causal effect of the JEE on crime. The staggered rollout and fixed-effects design strengthen the analysis by comparing changes over time across municipalities while controlling for municipality and year effects.

That is different from an ordinary correlation study. The question is not simply whether municipalities with longer school days had lower crime, but whether crime changed when municipalities adopted the program after accounting for systematic differences and common time trends.

Nevertheless, readers should keep the scope of the causal claim in mind. The study identifies the effect of the policy as implemented, not the effect of school hours in isolation. The JEE involved a broader institutional change in how schools used the day, and the research cannot reasonably be interpreted as proving that every additional hour of classroom instruction would generate the same result.

Nor does the study establish the precise behavioral mechanism responsible for the homicide reduction. The authors identify the human-capital and risk-behavior channels as being more consistent with the observed pattern than a pure incapacitation explanation. Those mechanisms remain interpretations of the evidence rather than directly observed causal pathways.

Why This Matters Beyond the Dominican Republic

The research addresses a broader question facing education systems around the world: what happens when governments increase the amount of time children and adolescents spend in structured educational environments?

Much of the existing research on education and crime has focused on wealthier countries. The Dominican study contributes evidence from a developing-country setting where education policy, social protection and public safety intersect in particularly visible ways.

It also illustrates why education policies should be evaluated across multiple outcomes. A school reform can affect learning, dropout, employment prospects, family time, adolescent behavior and public safety through different mechanisms, and those effects may not move in the same direction.

For the Dominican Republic, that broader perspective is particularly relevant because the JEE has become a major feature of the public-school system. MINERD’s later expansion of the model means that the policy now operates on a much larger scale than during the earlier stages examined in the study.

Future research can therefore ask questions that this study cannot fully answer: whether the observed homicide effects persist over longer periods, whether they vary across municipalities or socioeconomic groups, whether they differ according to school quality, and which components of the extended-school model are most closely associated with the changes in violence.

What Readers Should Take Away From the Research

The strongest conclusion is also the most carefully qualified one.

The Dominican Republic’s extended school-day program was not associated with a statistically significant reduction in crime overall. That finding should remain at the center of any accurate description of the research.

But the study also finds statistically significant reductions in male homicides and in homicides occurring outside school hours. Because those reductions occur beyond the hours when students are physically in school, the pattern is more consistent with longer-term behavioral or human-capital mechanisms than with simple supervision alone.

The car-theft results provide an important counterexample: total car thefts did not decline, while car thefts outside school hours increased significantly. That finding suggests that the policy may alter the timing of some criminal activity rather than uniformly suppressing it.

For the Dominican Republic, the broader implication is not that schools can replace policing or other crime-prevention measures. It is that education policy can have social effects extending beyond education, and those effects can be measurable in serious public-safety outcomes.

That is a more limited conclusion than saying longer school days reduce crime. It is also a more useful one. The evidence points to a potentially meaningful reduction in certain forms of severe violence while leaving overall crime unchanged. Understanding that distinction is essential for policymakers, researchers and international readers trying to assess what the Dominican Republic’s extended-school experiment can—and cannot—tell us about education and public safety.

Frequently Asked Questions

Did the extended school day reduce crime in the Dominican Republic?

Not overall. The study finds no statistically significant effect on aggregate crime measured through municipal homicide and car-theft rates. It does, however, find significant reductions in male homicides and homicides occurring outside school hours.

Did the study find fewer homicides?

It found significant reductions in specific homicide outcomes, particularly male homicides and homicides occurring outside school hours. It did not establish a statistically significant reduction in overall crime, and the finding should not be described as proof that all homicide declined because of the program.

What is the Jornada Escolar Extendida?

The Jornada Escolar Extendida is the Dominican Republic’s extended-school-day model for public education. It expanded the school day to roughly eight hours and incorporated additional educational, cultural, tutoring and student-support activities.

What crime data did the researchers use?

The researchers used municipal-level data on homicides and car thefts from the Dominican Republic’s National Statistics Office, or ONE, covering 2009–2019. They combined those data with administrative information from MINERD on the timing of JEE adoption.

Why did the researchers study car theft as well as homicide?

Car theft provides a nonviolent crime outcome that can help test whether the policy affected criminal behavior broadly or primarily influenced severe violence. The study found no significant effect on total car thefts but did find an increase in car thefts outside school hours.

Does the study prove that more time in school causes less violence?

The research is designed to estimate a causal effect of the JEE rollout, but its conclusions are narrower than that statement. It identifies significant reductions in particular homicide outcomes associated with the policy while finding no overall crime reduction. The precise behavioral mechanisms behind the results are not directly observed.

Could the findings be explained simply by keeping students off the streets?

That is one possible mechanism, but the timing of the results makes a purely mechanical explanation less convincing. The study finds no significant homicide reduction during school hours and does find a reduction outside school hours. The authors therefore consider human-capital and changes-in-risk-behavior mechanisms more consistent with the pattern.

Conclusion

The Dominican Republic’s experience with extended school days offers a useful lesson in how public policy should be evaluated: the most important finding may be more specific than the headline suggests. The JEE did not produce a statistically significant decline in crime overall, but its rollout was associated with fewer male homicides and fewer homicides outside school hours, while total car thefts remained statistically unchanged and car theft outside school hours increased.

Those results do not turn schools into a substitute for policing, criminal-justice institutions or other violence-prevention policies. They do suggest, however, that the social effects of education can extend beyond academic outcomes. In the Dominican case, the strongest evidence points to a selective reduction in serious violence rather than a generalized decline in crime.

For anyone assessing the country’s extended-school model, that distinction is not a technical footnote. It is the difference between what the evidence actually shows and a much broader claim the research does not support.