Chapter 9 Flashcards
Which study provides a snapshot of the health status of a population at one point in time?
Cross-sectional survey
Cross-sectional studies are also called:
Prevalence studies
Why are cross-sectional studies the most popular study approaches in the health sciences?
Because they allow for the rapid collection of new data
What is the goal of a cross-sectional survey?
To measure the proportion of the population with a particular exposure and disease
A cross-sectional study should be done over a ____(long/short) period of time based on a representative sample of a population.
Short
Cross-sectional surveys are used to:
1) Describe communities
2) Assess population needs
3) Support program planning
4) Monitor and evaluate programs
5) Establish baseline data prior to the initiation of longitudinal studies
What is epidemiology?
The study of the distribution and determinants of health of populations
Explain a cross-sectional study
The researcher asks a few hundred people to complete a short questionnaire, and then the data is analyzed.
What is one important requirement for the participants in a cross-sectional survey?
The participants must be reasonably representative of some larger population
What does representativeness mean?
The sample population must be as diverse as the source population
When do we do cross-sectional surveys?
1) The time is limited
2) The budget is small
What statistical measure do we use for cross-sectional surveys?
Prevalence
What is a KAP survey?
A commonly used type of cross-sectional study that asks participants about their Knowledge, Attitudes, and Practices.
KAP surveys can be particularly helpful for:
Identifying gaps between what people know and how they act on that knowledge.
Give an example on KAP survey.
The adults in the survey might demonstrate high knowledge about the benefits of exercise on cardiovascular health but at the same time indicate that they rarely exercise because a variety of perceived barriers prevent them from being as physically active as they know they ought to be for maximum fitness.
What does a repeated cross-sectional study do?
Re-samples and re-surveys representatives from the same source population at two or more different time points.
Which method is used for large studies conducted by the CDC?
Repeated cross-sectional surveys
Give three examples of repeated cross-sectional surveys
1) Behavioral Risk Factor Surveillance System (BRFSS)
2) National Health and Nutrition Examination Survey (NHANES)
3) U.S. National Health Interview Survey (NHIS)
True or false:
A repeated cross-sectional study design tracks the same individuals forward in time.
False; A new set of participants is sampled from the source population each time a survey is conducted.
Repeated cross-sectional surveys can reveal trends in:
Population-level metrics over time (NOT individual level changes)
Which study is used to study individual participants over a long period of time?
Longitudinal cohort study.
Cross-sectional surveys measure the prevalence of various:
1) Exposure histories
2) Disease states
3) Demographic characteristics
In one well-defined population at one point in time (or short period of time)
What is the most common way to report results for a cross-sectional survey?
By reporting the prevalence rate
What is the prevalence rate?
The percentage of the population with a given trait at the time of the survey.
What other ways can you report the results for a cross-sectional survey?
By comparative measures, such as prevalence rate ratios.
What are prevalence rate ratios?
They compare the prevalence of a characteristic in two population subgroups by taking a ratio of their prevalence rates.
Can cross-sectional surveys assess causality? Why or why not?
No they cannot, because a cross-sectional survey has no time dimension. We can say that an exposure can be “associated” or “related to a disease but we cannot show that an exposure caused a disease.
