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Table 4 Polio universe, source population, and study populations

From: Sampling method for surveying complex and multi-institutional partnerships: lessons from the Global Polio Eradication Initiative


Polio Universe Description

Estimated Universe Size (Target Population)

Operationalizing the Polio Universe

Proposed Sample (Source population)

Contact Plan

Study population


Individuals with knowledge and expertise of polio programs in the country from directly working in the polio eradication program. This included anyone who has worked directly in any level for policy formulation, policy implementation, program management, and field operation. To have an inclusive sample, Afghanistan’s Polio Universe was based on two frameworks; WHO health system building blocks and Afghanistan National Polio Eradication Initiative.


All national actors interviewed with online survey (206 identified)

All provincial EPI teams contacted with mobile phone survey (442 identified)

Purposively selected 7 provinces for in-person interviews


Online survey (31 respondents, 15.0% response rate)

Mobile Phone survey (126 respondents, 28.5% response rate)

In-person interviews (365 respondents)



Individuals who spent 12 or more continuous months working directly in implementing activities under the polio eradication program of Bangladesh between 1988 till date.


Snowball sampling to identify respondents due to lack of program intensity


Online survey (23 respondents)

In-person interviews (83 respondents)



Since Polio was integrated within the EPI Activities at the operational level, the Polio universe comprised all those dealing with it at different levels of the health pyramid, including external technical partners (such as WHO, UNICEF, Sabin Institute) and funding agencies (such as the World Bank, the BMGF, Rotary International, etc.)


Stratified health districts based on immunization coverage (good vs bad), history of polio epidemics, presence of AFP cases, and history of cVDPV outbreaks and randomly sampled districts by context type

Randomly sampled health areas within each district and then interviewed individuals within the health areas.


Online survey (136 respondents, 34.75% response rate)

In-person interviews (400 respondents)



The polio universe in Ethiopia included all individuals and partners who have been involved for 12 or more continuous months in implementing polio eradication activities in the country at national and/or sub-national levels (Region, Zone, District and health facilities); in public and/or private sector; and for NGOs between 1996 and 2018. It included individuals working at the national level (FMoH, national agencies such as EPHI and PSA, GPEI partners, NGOs, Professional Associations), Universities and Research Institutes, Regional Health Offices, Zonal and District Health Offices, Hospitals, health centers, health posts, public and private health facilities, religious and clan leaders, and communities and volunteers.

100,000 health workers who could have been involved in polio eradication

Purposively selected 5 regions (Addis Ababa, Benishangul-Gumuz, Gambella, Oromia, and Somali)


Online survey (2 respondents, 6.8% response rate)

In-person interviews (106 respondents)



The polio universe consisted of persons from Global Polio Eradication Initiative (GPEI) partner organizations, permanent and contractual employees of central and state government, members of national and international NGOs, teaching and non-teaching staffs of schools, medical and non-medical staff of different at levels of government hospitals and frontline health workers, media persons and volunteers. In addition, influencers from religious institutions like temples, mosques, church etc.

Estimated over 2.4 million people were involved in polio eradication

Stakeholder consultation workshop with high level actors enabled a list of 4,957 contacts


Online survey (352 respondents 7.1% response rate)

In-person interviews (165 respondents)



Actors who have spent 12 or more continuous months directly and indirectly for polio activities at national and sub-national level (provinces and districts) and restricted to time period between 1995-2014 (polio free certification)


Purposively selected six provinces (Aceh, Banten, West Java, DI Yogyakarta, East Java, East Nusa Tengarra)


Online survey

In-person interviews



A census of all actors who were involved in GPEI activities in Nigeria, from high level planners to project managers and field immunizers on a long-term basis (12 or more continuous months) within well-defined periods between 1988 and 2018. Partners that were involved in the survey include CDC, Rotary, WHO, UNICEF, NSTOP, NEOC, NPHCDA, Federal Ministry of Health, State Ministry of Health and Local Government Area level.


Purposively selected 10 states (Anambra, Bayelsa, Borno, FCT, Kano, Lagos, Nassarawa, Ondo, Oyo and Sokoto).

Randomly selected 4 Local Government Areas from each state


Online survey (793 respondents)

In-person interviews (160 respondents)


Global Survey

A population of individuals who have been directly involved in implementing activities under the GPEI between 1988 till date. Implementing activities refers to all cycles of implementation, including GPEI-related funding, policy, programming, and research cycles. The population includes individuals who have spent 12 or more continuous months working on activities under the GPEI between 1988 till date.

3,929 core staff active at the global level

Distributing the survey to all GPEI sub-groups

Gatekeepers from each organization to either provide contact information or distribute the survey within global organizations

GPEI listservs referring individuals to a webpage with the survey


Online survey (891 respondents)


Definitions and Totals

Across 7 countries and global staff dedicated to polio eradication from 1988 to date, the estimated polio universe:


Across 7 countries and the global staff dedicated to polio eradication, the number of individuals who could be reached to take the survey:


Number of respondents included in the study population