Background
The definition of target, source, and study populations are interrelated and are a starting point for the methods described in this paper. These concepts are defined as follows [4]; • Target Population: The collection of individuals, items, measurements, etc., about which inferences are desired. The term is sometimes used to indicate the population or group from which a sample or study population is drawn and sometimes to denote a reference population about which inferences are desired • Source Population: The group from which a study group is selected • Study Population: The group selected for investigation. |
Initiative/ Study | Objective of Study | Target Population | Source Population | Study Population |
---|---|---|---|---|
External Evaluation Of The President’s Malaria Initiative (PMI) [13] | Review the first five years (FY06-FY10) of PMI’s activities, organized around six core objectives | Not described | Focus on key actors, both internal and external to PMI. Not quantitatively described 5/15 focus countries visited | 65 respondents with described position/role |
Five Year Evaluation of the Global Fund: Study Area 1; Organizational Development study [14] | Assess organizational efficiency and effectiveness of the Global Fund, | Described staff in terms of unit (7 types) and level (3; senior managers, managers, and other staff). Total staff estimates were not quantitatively described | 283 Secretariat staff at the time of evaluation | 89 Secretariat staff were involved (33 in pre-assessment meetings that identified 56 additional respondents) |
Five Year Evaluation of the Global Fund: Study Area 2 [15] | Assess effectiveness of the Global Fund partnership environment | Not described | Partners and stakeholders at the country and global levels; grant recipients and implementing partners at the country level; fund portfolio managers at the Secretariat; technical assistance partners at the country and global levels; civil society representatives. 16 focus countries | Over 900 individuals interviewed |
Evaluation of the President’s Emergency Plan for AIDS Relief (PEPFAR) [16] | Assess PEPFAR's performance and its effects on health | Described interviews conducted in terms of 8 roles across countries Total staff estimates were not quantitatively described | Individual source population not described 31 focus countries, 13 of which were visited | 383 interviews conducted across the 8 roles and country contexts |
Second Gavi Evaluation [17] | Assess the extent to which Gavi met its four strategic goals and the extent to which it has added value at global and country levels | Stakeholders of Gavi; 4 internal roles and 7 external roles described. Total stakeholder estimates were not quantitatively described | Online survey sent to 1,000 stakeholders Manager survey sent to 76 Expanded Program on Immunization managers | 282 responses received, including half from partner institutions 23 responses received 109 consultations with roles described |
Synthesis and translation of research and innovations from polio eradication
Results
Defining levels of representation
Country Polio Epidemiologic Contexts as of 2018 (and STRIPE focus countries) | Examples of Organizational and Operational Levels | Polio Goals |
---|---|---|
Polio Endemic: • Afghanistan • Nigeria Outbreak: • DRC High risk: • Ethiopiaa Polio free: • Bangladesh • India • Indonesiaa | • Core GPEI members ○ BMGF, CDC, Rotary, UNICEF, WHO ○ Regional polio surveillance laboratories • Country government officials ○ State, District, and local level government ○ Subnational monitoring boards ○ Vaccinators • Civil Sociey Organizations ○ International Non-Government Organizations ○ Local Non-Government Organizations ○ Community organizers ○ Local and religious leaders • Other donor organizations and development partners ○ International development partners (USAID, DFID, etc) ○ Local donors/development partners | • Resource mobilization • Partnership/alliance development • Strategy development and planning • Strengthening delivery services • Vaccination • Surveillance • Community Engagement • Monitoring and Evaluation |
Theorizing a target population: the polio universe
Country | Polio Universe Description | Estimated Universe Size (Target Population) | Operationalizing the Polio Universe | Proposed Sample (Source population) | Contact Plan | Study population |
---|---|---|---|---|---|---|
Afghanistan | 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. | 185,041 | 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 | 65,041 | Online survey (31 respondents, 15.0% response rate) Mobile Phone survey (126 respondents, 28.5% response rate) In-person interviews (365 respondents) | 522 |
Bangladesh | Individuals who spent 12 or more continuous months working directly in implementing activities under the polio eradication program of Bangladesh between 1988 till date. | 51,500 | Snowball sampling to identify respondents due to lack of program intensity | 140 | Online survey (23 respondents) In-person interviews (83 respondents) | 106 |
DRC | 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.) | 300,000 | 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. | 85,000 | Online survey (136 respondents, 34.75% response rate) In-person interviews (400 respondents) | 536 |
Ethiopia | 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) | 150 | Online survey (2 respondents, 6.8% response rate) In-person interviews (106 respondents) | 108 |
India | 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 | 4,957 | Online survey (352 respondents 7.1% response rate) In-person interviews (165 respondents) | 517 |
Indonesia | 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) | 103,252 | Purposively selected six provinces (Aceh, Banten, West Java, DI Yogyakarta, East Java, East Nusa Tengarra) | 32,502 | Online survey In-person interviews | 322 |
Nigeria | 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. | 14,064 | Purposively selected 10 states (Anambra, Bayelsa, Borno, FCT, Kano, Lagos, Nassarawa, Ondo, Oyo and Sokoto). Randomly selected 4 Local Government Areas from each state | 3,906 | Online survey (793 respondents) In-person interviews (160 respondents) | 953 |
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 | 1,400 | Online survey (891 respondents) | 891 |
Definitions and Totals | Across 7 countries and global staff dedicated to polio eradication from 1988 to date, the estimated polio universe: | 3,157,786 | Across 7 countries and the global staff dedicated to polio eradication, the number of individuals who could be reached to take the survey: | 193,096 | Number of respondents included in the study population | 3,955 |
Enumerating the source population
Obtaining a comprehensive sample
Reflecting on the obtained sample
Generalizing to other complex initiatives
(i) State research goal(s) | |
(ii) Describe the program of interest | |
(iii) Define a sampling universe to meet these criteria | |
(iv) Estimate the size of the sampling universe | |
(v) Enumerate a source population within the universe that can be feasibly reached for sampling | |
(vi) Sample from your source population (collect data) | |
(vii) Reflect on the process to determine strength of inferences drawn |