Gaps in population data for health programs
Every population figure used to plan a vaccination drive is an estimate based on assumptions about fertility, mortality, and migration. This is not a flaw in the Philippine Statistics Authority’s (PSA) work; it is the nature of population projections. The problem arises when estimates are not validated against conditions on the ground.
In public health, these figures determine vaccine allocations, health worker evaluations, and whether communities are classified as underserved. The gap between projection and reality becomes a shortage, a surplus, or a failing grade.
When estimates become targets. Under the Philippine Statistical Act of 2013, the PSA serves as the government’s central statistical authority. Its projections inform local vaccination targets and vaccine requests under the Mandatory Infants and Children Health Immunization Act of 2011.
The Department of Health (DOH) targets 95 percent full immunization coverage under its National Immunization Acceleration Plan. Yet PSA National Demographic and Health Surveys have reported coverage of only 70-80 percent over three decades. This shortfall is commonly attributed to poor program performance, with little scrutiny of whether projected populations reflect the children actually living in each locality.
The issue is not that projections are imperfect, which is inevitable, but that their limitations are rarely actively managed.
The gap on the ground. In a province in Region XIII, the fully immunized child rate sits at 64.4 percent, well below the national target. Health workers in one municipality report having vaccinated nearly every child they can locate, including in health stations, public markets, and even across municipal lines. Yet the area’s official rate has held near 50-60 percent since 2017.
Population movement may explain the discrepancy. Transient mining communities can increase local populations, while indigenous and geographically isolated families may relocate to settlements outside their registered barangays. Children may be counted in one area but live in another, distorting coverage figures.
Because PSA-based figures feed into the local government units (LGUs) Health Scorecard and the Seal of Good Local Governance, health workers describe being asked to locate children who do not exist in their catchment areas. Some LGUs already conduct household profiling, yet these actual counts carry little weight when performance is measured against original projections.
Oversupply, wastage, and vaccine hesitancy. The same projections guide vaccine allocation. Doses shipped to localities with fewer children than projected can exceed demand and expire unused, particularly during supplemental immunization activities against diseases such as measles and rubella.
Vaccine hesitancy is another challenge. Some patients refuse vaccination because they believe vaccines contain pork-derived ingredients that conflict with their religion; others fear vaccines after watching misinformation online. These are genuine barriers, but they differ from inaccurate population estimates. A locality that has reached nearly all its children can look identical in the data to one where patients refuse vaccination. Without distinguishing these causes, policymakers cannot design appropriate responses.
Applying projections without mechanisms for local correction damages health workers’ morale and undermines immunization data. Less reliable data weaken outbreak response planning, coverage assessments, and the evidence base for Universal Health Care.
A practical way forward. This is not an argument against the PSA or its projections, which remain essential for national planning. It is an argument for managing their limitations.
The DOH, PSA, and LGUs should regularly validate projections against civil registration records, household profiling, migration patterns, the Registry of Barangay Inhabitants and Migrants, and the community-based monitoring system. Regional and provincial health offices should use these comparisons to adjust targets and align vaccine procurement with local needs, allowing surplus doses in one LGU to offset shortages in another.
Population projections are estimates, not scandals. The real failure is allowing their imperfections to become unquestioned targets—and leaving health workers and communities to bear the consequences.
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Dr. Kenneth Hartigan-Go is a senior research fellow at the Health Governance Program of the Ateneo Policy Center, School of Government. Dr. Daisy Ilagan-Tagarda is a nonresident research fellow and Nathan Santos is a research assistant at the center. Dr. Alberto Antonio Jr. is a former DOH doctor to the barrios. The views expressed herein are those of the authors and do not necessarily reflect the views of Ateneo de Manila University.
