The document discusses two research designs: cross-sectional and longitudinal. Cross-sectional studies collect data from a population at a single point in time, providing insights but facing limitations such as cohort differences and participant variability. Longitudinal studies track the same individuals over time, allowing for better causal inferences but are often time-consuming, costly, and may suffer from participant dropout.

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Name of Presentation
1.Cross-Sectional Study Design
2.Longitudinal Study Design

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Cross-Sectional Study Design
 Cross-Sectional Survey Design A cross-
sectional survey collects data to make
inferences about a population of interest
(universe) at one point in time.
 Cross-sectional surveys have been described
as snapshots of the populations about which
they gather data.
 Cross-sectional surveys may be repeated
periodically.

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Cross-Sectional Study Design
 Cross-sectional surveys can thus be contrasted
with panel surveys, for which the individual
respondents are followed over time.
 Cross-sectional surveys can be conducted using
any mode of data collection, including telephone
interviews, face-to-face interviews, mailed
questionnaires.

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Defining Characteristics
 Takes place at a single point in time
 Does not involve manipulating variables
 Allows researchers to look at numerous things at once (age,
income, gender)
 Often used to look at the prevalence of something in a given
population

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Topics of Cross-Sectional Study Design
The health needs of a Community.
The Attitudes of students towards the
facilities available in their library.
Consumer satisfaction with their products.

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Limitation Cross-Sectional Study Design
 While the design sounds relatively simple, finding participants
who are very similar except in one specific variable can be
difficult.
 Groups can be affected by cohort differences that arise from the
particular experiences of a unique group of people.
 Individuals born in the same time period may share important
historical experiences, while people born in a specific geographic
region may share experiences limited solely to their physical
location.

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Longitudinal Study Design
 Longitudinal Study Any social or developmental research
involving collection of data from the same individuals (or
groups) across time.
 Observing change in these individuals gives a better basis
for causal inference than a cross-sectional study, because of
the temporal sequencing involved. In this sense the
longitudinal study is a form of ‘quasi-experimental design’.

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Longitudinal Study Design
 Longitudinal studies can range from repeated measures of a
treatment group and a control group measured at two time
points in an experimental design, to a large-scale long-term
birth cohort study, involving follow-ups of the same sample
of individuals from birth through to adult life.
 Longitudinal studies allow social scientists to distinguish
short from long-term phenomena, such as poverty. If the
poverty rate is 10% at a point in time, this may mean that
10% of the populations are always poor, or that the whole
population experiences poverty for 10% of the time. It is not
possible to conclude which of these possibilities is the case
using one-off cross-sectional study.

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Limitation of Longitudinal studies
 longitudinal studies require enormous amounts of time and are
often quite expensive.
 These studies often have only a small group of subjects, which
makes it difficult to apply the results to a larger population.
 Another problem is that participants sometimes drop out of the
study, shrinking the sample size and decreasing the amount of
data collected.

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Limitation of Longitudinal studies
 longitudinal studies require enormous amounts of time and are
often quite expensive.
 These studies often have only a small group of subjects, which
makes it difficult to apply the results to a larger population.
 Another problem is that participants sometimes drop out of the
study, shrinking the sample size and decreasing the amount of
data collected.