Epidemiology Study on Prevalence of Respiratory Symptoms and Atopic Disease in Indigenous and Non-Indigenous Children in ACT

Running head: Epidemiology 1
Epidemiology
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Epidemiology 2
1. What is the research question of this study? (2 marks)
What is the prevalence of respiratory symptoms and atopic disease in Aboriginal and Torres
Strait Islander (indigenous) and non-indigenous children in the Australian Capital Territory
(ACT)?
2. What type of design was used to complete this study? Please give as much detail in terms of
the general design as you can. (3 marks)
A two-stage questionnaire survey. Questionnaires are appropriate for a large population because
they are fast and the collected data can easily be compared. They provide quantifiable answers
for a research topic. However, varying responses may make it difficult to analyze.
3. Was the overall study design appropriate for the research question? Please explain your
answer fully. (3 marks)
The two-stage questionnaire design was appropriate for the study because it is free from
researcher bias of the interviewer because the feedbacks are the respondent’s own words.
Moreover, the respondents have sufficient time to provide well thought out answers. Since the
analyzed sample was large, a two-staged questionnaire was appropriate because it enables easy
and effective data collection and the outcomes more reliable.
4. What was the population of interest? (3 marks)
All new entrant primary schoolchildren aged 4–6 years
5. Do you think the sample sizes of the surveys for the two groups of interest have an impact on
the quality of the study? (2 marks)

Epidemiology 3
Yes. The size of the two samples varies significantly. A very small sample size reduces the
power of the study and increases the margin of error which makes the study useless (Faber &
Fonseca, 2014). On the other hand, the sample size for the non-Indigenous group is too large
which complicates statistical tests because they were made to handle samples and not
populations. This increases the analysis power and high tendencies to reject the null hypothesis.
6. Please comment about the response rates of the surveys and how these impact on the quality of
the study. (3 marks)
The response rate for the kindergarten was 80%. A response rate of 80% has high
representativeness of the population and thus there is an assurance that the sample participants
reflect the elements in the general population. This increases the quality of the study because a
high response rate reduces nonresponse bias (Davern, 2013).
7. Please discuss the likelihood of selection bias in this study. Can you think of at least two
possible sources of selection bias in this study? (3 marks)
There is a possibility of selection bias in the parental questionnaire (self-selection). The parents
responsible for selecting the children participants with respiratory symptoms may not select
some of their children due to privacy or they may be impartial in the selection. Secondly, all
children in the ACT identified by the parents were to be included in the study. There is a
possibility of selection bias because all children were to be included and yet there was no
randomization in the selection.
8. What was the primary exposure variable in this study? Please explain your choice of this
variable. (2 marks)