Education | César Garro-Marín

When Teacher Training Doesn't Work

Thu, 04 Jun 2026 00:00:00 +0000

Every year, governments spend millions trying to make their teachers more effective. The logic is intuitive: better-trained teachers deliver better lessons, and better lessons produce better students. In developing countries, where teachers often have limited subject expertise and schools are under-resourced, professional development programs are used very often (Popova et al., 2022).

Indonesia is a good test case. Globally, vocational high schools serve more than 48 million students across low- and middle-income countries (EdStats, 2022). Indonesia alone has over five million students enrolled in vocational secondary schools—half of all secondary enrollment. With a persistent gap between what schools teach and what employers need, the government has made upgrading teacher skills a top priority.

A promising design

The program studied in our paper had an appealing design. Rather than relying on the government itself to retrain teachers, the government contracted private-sector firms—the companies that actually hire vocational graduates—to deliver intensive, field-specific training to teachers. Lasting six to eight weeks on average, the courses were substantially longer than the typical teacher professional development program worldwide, which runs just two and a half weeks (Popova et al., 2022).

The intuition was compelling: who better to teach welding, nursing, or electronics than the firms that use these skills every day? Teachers would spend time learning up-to-date, industry-relevant techniques and bring that knowledge back into the classroom. At scale, this could make vocational schooling genuinely useful for the labor market.

We used a randomized evaluation to test this idea: some teachers were selected to participate in the program, others were not—similar to a clinical trial for a new medicine. This setup allows a clean comparison of what happened in program schools versus control schools.

The results were discouraging

The program failed to deliver on its promise:

No increase in overall training. Teachers in program schools were nearly twice as likely to participate in the new program as those in control schools—and their exposure to the private sector increased by 16 percentage points. Yet they received no more training overall. The new program simply replaced professional development they were already doing elsewhere. Economists call this crowding out: a new intervention displaces existing activity rather than adding to it.
No improvement in teacher knowledge. Despite intensive delivery by industry professionals, teachers’ content knowledge in their vocational fields did not improve. Our estimates rule out effects larger than 0.15 standard deviations — far below the 0.2 to 0.4 standard deviation gains typical of intensive teacher training programs in other contexts (Fryer, 2017).
No improvement in school quality. Broader measures of school performance — including school accreditation scores — showed no meaningful change.

The program changed what type of training teachers received, not how much they learned or taught.

Why didn’t it work?

Three patterns from our survey help explain the null results. First, the training was not tailored to actual skill gaps: approximately 80% of attendees reported already being familiar with the materials covered. Second, teachers had limited support for translating training into sustained classroom change — only 26% reported any follow-up sessions after the program ended, and more than half said they needed stronger leadership support at their school. Third, control-group teachers had access to alternative, vocational-specific training elsewhere, making the new program less of an addition and more of a substitution.

Potentially more ICT use

There was a single exception to the null results: teachers in program schools showed some evidence of increased use of Information and Communication Technologies in the classroom. The ICT-focused elements of the training appear to have stuck where the vocational content did not — perhaps because ICT skills were genuinely new for most teachers, leaving less room for crowding out.

What this means

The findings carry lessons well beyond Indonesia:

Crowding out is a hidden risk. When a new program replaces existing training rather than supplementing it, even a well-designed intervention can have no net effect. Policymakers should measure total training participation — not just take-up of the new program — before declaring success.
Target skill gaps, don’t assume them. The fact that 80% of attendees already knew the training materials suggests the program was not matched to what teachers actually needed. Future programs should begin with careful needs assessments.
Industry delivery is not a magic ingredient. Firms are good at doing their own jobs. That doesn’t automatically make them good at teaching. The mechanism linking industry involvement to teacher improvement needs to be understood and tested, not assumed.
Follow-through matters as much as training. Without sustained support after the course ends, even good training rarely translates into lasting changes in classroom practice.

References

EdStats. 2022. “Education Statistics.” World Bank. https://datatopics.worldbank.org/education.
Fryer, R G. 2017. “The production of human capital in developed countries: Evidence from 196 randomized field experiments.” In Handbook of Economic Field Experiments, Vol. 2, 95–322. Elsevier.
Popova, A, D K Evans, M E Breeding, and V Arancibia. 2022. “Teacher Professional Development around the World: The Gap between Evidence and Practice.” The World Bank Research Observer, 37(1): 107–136.

Co-authored with: Masyhur Hilmy (University of New South Wales)

Status: Submitted

Learn more: Full Paper

Who Benefits When Governments Build Schools?

Thu, 04 Jun 2026 00:00:00 +0000

When a government builds 6,000 new schools in 15 years, adding millions of seats for teenagers who could not previously access high school, it seems impossible for the effort to fall short. But “fall short” is not the right question. The right question is: who actually shows up?

In the late 1990s, only about 40% of Indonesian teenagers were enrolled in high school—well below the 60% rate in East Asia and the Pacific and 49% among middle-income countries (The World Bank, 2025). Starting in the early 2000s, the government launched an ambitious construction drive, building over 6,000 public high schools and adding more than 2.4 million seats over 15 years. The expansion targeted districts with the lowest enrollment rates, where the need was greatest.

The standard case for building more schools

The logic behind school construction programs is intuitive. Where schools are scarce and travel distances are long, young people don’t enroll. Build the school, lower the costs, and enrollment rises. If you target the most underserved districts, the gains should flow to those who need them most.

In mixed public-private education markets, there is an additional concern: will new public schools simply pull students away from private providers, leaving overall enrollment unchanged and damaging a sector that many families depend on?

What happened in Indonesia

Our paper compares districts that received new schools earlier against those that received them later, tracking enrollment and private school outcomes over time.

On enrollment, the expansion worked. Within five years of a district receiving new schools, upper-secondary enrollment rose by roughly 4 percentage points—about a 12% increase relative to the baseline rate. There were also positive spillover effects: middle school enrollment rose too, as students became more likely to stay in school when they could see a path forward to high school.

The new construction did not crowd out private schools. In the United States, increased public school funding has been shown to drive private school closures (Dinerstein and Smith, 2021). In Indonesia, private school construction in expansion districts did not slow down—if anything, it ticked up slightly in the years after the public expansion began. Private school students did not score worse on exit exams either. In settings where secondary enrollment is low to begin with, expanding public supply appears to grow the overall market rather than just redistribute existing students.

Enrollment gains concentrated among boys

The enrollment gains were deeply unequal across groups:

Boys from more educated families benefited most: high school attendance in this group rose by over 6 percentage points.
Girls saw smaller gains of about 3 percentage points, concentrated among girls from less-educated households.
Students from disadvantaged backgrounds gained far less at the high school level.

This pattern inverts what happens at the middle school level, where school expansions tend to reach the most disadvantaged students. The difference suggests that at the high school level, barriers go beyond physical access.

Building a school nearby likely reduces costs. But it does not address the other reasons families keep teenagers—especially girls—out of school.

Why the gap?

When secondary enrollment is already low, the students closest to enrolling are not the most disadvantaged—they are the ones who face the fewest other obstacles. Boys from educated families already have the demand; the new school removes the final constraint. Girls and children from poorer households face additional barriers: family economic pressure, safety concerns about longer journeys, and social norms that deprioritize education beyond a certain level. A new building does not change any of those.

What this means

School construction is necessary but not sufficient. Reducing physical and financial costs helps—but other barriers remain for girls and disadvantaged students. Scholarships, transport support, and community engagement are needed alongside new buildings to make sure they reach the students who need them most.
Public expansion need not hurt private schools. Policymakers worried that public construction will undermine private providers can take some reassurance. In low-enrollment contexts, there is room for both sectors to grow simultaneously.
Who benefits matters as much as how many benefit. A program that raises average enrollment while widening gaps between advantaged and disadvantaged students is not fulfilling its equity mandate. Monitoring enrollment by gender, parental education, and household income should be standard practice for any school-building program.
The case for demand-side policies is stronger than it looks. Conditional cash transfers, girls’ scholarships, and efforts to shift norms around girls’ education are not nice-to-haves—they are what determines whether supply-side investment reaches the intended beneficiaries.

References

Dinerstein, M and T D Smith. 2021. “Quantifying the supply response of private schools to public policies.” American Economic Review, 111(10): 3376–3417.
The World Bank. 2025. “Education Statistics – All Indicators (EdStats) DataBank.”

Co-authored with: Masyhur Hilmy (University of New South Wales)

Status: Working paper

Learn more: Full Paper