Innovating survey methods to strengthen childhood immunization in the Philippines

Decision-maker’s challenge

The Philippines has made significant strides in reducing the number of zero-dose children, but persistent inequities remain. As of 2023, the country brought that number down by around 84%, from over one million in 2021 to 163,000 in 2023 (WHO). Yet in many rural and underserved areas, children continue to miss routine vaccinations due to access barriers, information gaps, or lack of trust in the system. 

To close these remaining gaps, the Department of Health (DOH) needs timely, reliable data to understand what stops caregivers from accessing services. However, collecting Behavioral and Social Drivers (BeSD) data through traditional face-to-face surveys is costly, slow, and difficult to scale nationwide.

In collaboration with the Task Force for Global Health (TFGH) and the Department of Health (DOH), IDinsight evaluated whether digital surveys could offer a reliable, cost-effective alternative. The aim was to inform targeted interventions and strengthen DOH’s capacity to respond more quickly to shifting vaccine demand.

Impact opportunity

Vaccination remains one of the most effective and affordable public health tools available, preventing an estimated 4 to 5 million deaths globally each year. As the Philippines approaches universal coverage, the priority is to identify and address the remaining bottlenecks.

This study tested whether remote data collection methods, which are lower-cost than traditional in-person surveys, could generate timely, actionable BeSD insights. If proven effective, such tools would allow DOH to monitor emerging barriers more frequently and adapt its outreach accordingly. The work also contributes to broader global efforts to assess the tradeoffs involved in remote survey modalities in low- and middle-income settings.

Our approach

We partnered with DOH and local stakeholders to test three survey modalities in two regions with low vaccination coverage:

• In-person interviews conducted by trained enumerators using SurveyCTO
• Mobile phone surveys via short messaging service (SMS) and interactive voice response (IVR) using engageSPARK
• Online chatbot surveys delivered through DOH’s Knowledge Informs Responsible Action (KIRA) platform hosted on DOH’s Facebook page, in partnership with AI4GOV

We surveyed 3,674 caregivers of children under two. We tailored every tool to the local context, simplifying questions, translating into local languages, and engaging barangay(community) health workers (BHWs) to recruit and assist participants. We simplified and translated survey content, recruited through barangay health workers (BHWs), and embedded multiple quality controls—including backchecks, audio audits, and weighting adjustments.

In partnership with AI4GOV, data from all three surveys was linked to DOH’s KIRA dashboard to support real-time use and planning. We also held regional dissemination workshops to translate findings into action.

The results

Remote surveys, while not a substitute for in-person interviews, proved effective for capturing key attitudinal indicators such as vaccine confidence. They were also significantly faster and more affordable: mobile surveys cost roughly one-fourth (SMS/IVR) to one-tenth (online) of the cost per completed response compared to face-to-face.

However, these tools come with tradeoffs. Mobile modes reached a narrower demographic—primarily younger and more educated caregivers—and performed less reliably on sensitive or complex indicators such as intent to vaccinate or confirmed zero-dose status. These limitations underscore the importance of pairing remote surveys with thoughtful sampling strategies, proper framing, and behavioral nudges to improve both reach and data quality.

Despite these constraints, the surveys revealed consistent and actionable barriers across regions: long clinic wait times, transport costs, and being turned away due to stockouts. These findings helped surface actionable priorities for DOH regional offices, several of which expressed interest in integrating BeSD indicators into existing planning forms and outreach strategies.