Impact of methodological

Table 7 Sensitivity analysis: potential bias introduced by excluding a proportion of the population. Commonwealth of the Northern Mariana Islands, 2005.

			Estimated Vaccination Coverage*
	% of Population		1 year	2 years	6 years
Eligibility Determined in Study
Determined	94.0		91.8	82.4	83.0
Not Determined^†	6.0	Lower Bound	87.7	73.6	74.5
		Upper Bound	95.9	91.2	91.5
Weighted Average		Lower Bound	91.6	81.9	82.5
		Upper Bound	92.0	82.9	83.5
Availability at Initial Visit
Available	79.3		91.5	80.2	83.3
Not Available^‡	20.7	Lower Bound	83.0	60.4	66.6
		Upper Bound	95.8	90.1	91.7
Weighted Average		Lower Bound	89.7	76.1	79.8
		Upper Bound	92.4	82.2	85.0
Accessibility
Saipan	88.4		91.9	82.1	83.2
Rota/Tinian^§	11.6	Lower Bound	83.8	64.2	66.4
		Upper Bound	96.0	91.1	91.6
Weighted Average		Lower Bound	91.0	80.0	81.3
		Upper Bound	92.4	83.1	84.2
Observed Coverage			91.8	82.4	83.0

*Children aged 1 year: received at least 3 doses of diphtheria-pertussis-tetanus vaccine (DPT), 3 doses of inactivated poliovirus vaccine (IPV), 2 doses of Haemophilus influenzae type b vaccine (Hib) and 3 doses of hepatitis B vaccine. Children aged 2 years: received at least 4 doses of DPT, 3 doses of IPV, 1 dose of measles-mumps-rubella vaccine (MMR), 3 doses of Hib, and 3 doses of hepatitis B. Children aged 6 years: received at least 5 doses DPT, 4 doses of IPV, 2 doses of MMR, and 3 doses of hepatitis B vaccine.
^†Coverage assuming children in households for which eligibility was not determined were twice as likely to be unvaccinated (lower bound) and half as likely to be unvaccinated (upper bound) as those for which eligibility was determined in the study.
^‡Coverage assuming children not available were twice as likely to be unvaccinated (lower bound) and half as likely to be unvaccinated (upper bound) as those available at the initial visit.
^§Coverage assuming children living on Rota and Tinian were twice as likely to be unvaccinated (lower bound) and half as likely to be unvaccinated (upper bound) as those on Saipan.

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