1. Discuss the results presented in table HH.1 and describe the importance of this table

in any survey.

Of the 42,981 households sampled, 28,413 live in rural areas, or 66% of households. For this purpose, 34% of households are in urban areas. 41059 households have at least one mother or caregiver present at the time of the survey. However, 98.7% of them have a mother or caregiver who agrees to be interviewed, ie 40518 households.

Of the 6360 mothers or caregivers of children aged 12 to 23 months eligible for the survey, 6268 of them were interviewed during the survey, a response rate of 98.6%. About 71% of mothers or caregivers of children aged 12 to 23 months surveyed live in rural areas and 29% live in urban areas.

In any survey, this table is important for two reasons:

• Representativeness that requires that the sample structure is the same as that of the population:

According to the results of the RGPH in Africa, the urban population is most often around 2/3 of the total population. And our sample here is around this percentage

• The non-response rate must be low (less than 10%), which is our case.

2. From tables HH.3 and HH.5, (a) describe the key differences between weighted and unweighted household composition findings. (b) What factors would influence the differences observed between the weighted and unweighted results.

In relation to the composition of the household

Before weighting, female heads of households are overrepresented and male heads of households are underrepresented. Similarly, the most populated area, the north-west is under-represented in the sample while the south-south (the least populated area after the southeast) is over-represented.

In relation to the ethnicity of the head of the household, it is observed that the majority ethnic group, the Hausa, is under-represented in the sample.

For children from 12 to 23 months:

The number of male children sampled is small relative to the size of the population. On the other hand, the religion of the parents is overrepresented in the sample.

The factors that influence these weights are:

Gender of head of household, sex of child, ethnicity, place of residence, area of residence…

3. The results of table IM.1 are based on a weighted analysis (a) Discuss the findings of

table IM.1 (b) How does sample size influence the findings in table IM.1? (c) Describe

what would be the key differences in results of table IM.1 if they were computed on

the unweighted sample.

In Nigeria, the percentage of children vaccinated remains low. Between 2016-2017, less than the majority of children aged 12 to 24 months were vaccinated with penta 1 and few of these children (33%) completed penta 3. The existence of cards remains problematic. In fact, 29% of children aged 12 to 24 months have been vaccinated and have vaccination cards.

The size of the sample reduces the percentages of children vaccinated according to the context of residences and certain characteristics (mother's gender, level of education ...)

The key differences are:

• In terms of vaccine coverage rates in the North, particularly for penta 1, penta 2 and penta 3;

• In terms of percentages of immunized children aged 12 to 23 months living in households in the fourth wealth quintile.

4. If a survey has “low” card availability, would you do the analyses that require dates

(timelines, simultaneity of vaccines recommended at the same age, missed

opportunities) weighted or unweighted? Why? Explain.

Yes

5. (a) With reference to table IM.14 describe key differences between crude and valid

coverage. (b) How does card availability (and with dates) influence computation of

valid coverage?

For the crude, we are interested in vaccinated children at any age, while for the net coverage, we are interested in children aged 12 to 23 months vaccinated