Table 1.

Sampling strategy, data collection methods, and types of data collected for addressing the five study objectives.

Objective	Sampling strategy	Data collection methods	Type of data collected
1. Assess and compare infrastructure, capacity, and human resources needs in 2 provinces that represent different levels of readiness	All immunization health facilities (N=1026) in Ha Noi and Son La Provinces	Self-filled forms in Kobo toolbox sent via email	Immunization services provided: EPIa, non-EPI, and hepatitis B birth dose vaccine coverage Infrastructure conditions: electricity, computers, type of internet connection, barcode printers, and readers Current NIISb use: NIIS log-in and username End users implementing the NIIS: number of people trained in use of NIIS or need for additional trainings Indicators for data accuracy: data entry for immunizations and stock balances
2. Assess NIIS end users’ perceptions and feedback	A total of 767 districts and communes were purposively selected	Self-filled forms in Kobo toolbox sent via email	Time spent planning and reporting before and after NIIS Perceptions of NIIS system on managing data and quality of data Feedback for system improvement
3A. Evaluate data quality between immunization cards and the NIIS	Son La: All children born after July 1, 2017, purposefully selected from 1 village in each of the 6 selected communesc Ha Noi: 7d children born after July 1, 2017, in each village or living quarter identified door-to-door, in each of the 12 selected communesc	Review and compare data between immunization cards and the NIIS	Immunization data on immunization cards of selected children Immunization data in the NIIS of selected children
3B. Evaluate data quality between paper-based records and the NIIS	20 randomly selected children from each of 14e purposefully selected fee-based facilities and hospitals	Review and compare data between paper-based logbooks at health facilities and the NIIS	Immunization data written in the facility paper-based logbook of selected children Immunization data in the NIIS of selected children
3C. Evaluate data quality between paper-based records and the NIIS for BCGf vaccination administered in previous month	18 randomly selected commune health centers and district health centers	Review and compare count of BCG immunizations among children in facility paper-based logbooks and in NIIS for previous month	Number of children vaccinated in previous month with the BCG vaccine per paper-based logbook Number of children vaccinated in previous month with the BCG vaccine in the NIIS
4. Compare the accuracy of stock data that were physically counted to stock data in the NIIS	Random selection of 3 vaccine lots in 30 health facilities with established NIIS system	Review of actual stock of 3 randomly selected vaccine lots and in NIIS	Physical stock balance of selected lots Stock balance per NIIS of selected lots
5. Evaluate the knowledge and skills of NIIS end users	Convenience sampling of 1 or 2 NIIS end users from each purposefully selected fee-based facility and hospital	Observation and interviews with NIIS end users	NIIS knowledge and skills of end users using the three modules: immunization registry, stock management, and reporting

^aEPI: Expanded Program on Immunization.

^bNIIS: National Immunization Information System.

^cOverall, 6 out of 30 districts in Ha Noi and 3 out of 12 districts in Son La.

^dDue to the large population size in Ha Noi province, the World Health Organization’s 30-clusters methodology was applied.

^eOne hospital that did not use the NIIS at the time of survey was excluded.

^fBCG: Bacillus Calmette-Guérin.