Study Design Flashcards
perpek
is a specific plan or protocol for conducting study, which allows the investigator to
translate the conceptual hypothesis into an operational one
Study Design
a study design where participants are
randomly assigned to either a treatment group or a control group to test the effectiveness of a
new medication.
randomized controlled trial
Studies that do not involve any intervention or experiment.
Observational
Studies that entail manipulation of the study factor (exposure) and randomization of subjects to treatment (exposure) groups.
Experimental
Non-experimental
Observational Studies
Observational because there is no individual intervention
Observational Studies
Treatment and exposures occur in a “non controlled” environment
Observational Studies
Individuals can be observed prospectively, retrospectively or currently
Observational Studies
Case Reports
Descriptive Studies
Detailed presentation of a single case or handful of cases.
Descriptive Studies
Generally report a new or unique finding:
*previous undescribed disease
*unexpected link between diseases
*unexpected new therapeutic effect
*adverse effects/events
Descriptive Studies
To observe and analyze
relationships between
variables without manipulation
by the researcher.
Observational Study
Typically focuses on
understanding relationships,
associations, or patterns
between variables.
Observational Study
Analyzes relationships
between variables using
statistical techniques.
Observational study
To describe characteristics,
behaviors, or phenomena
without manipulation or
intervention
Descriptive Study
Typically focuses on
describing characteristics,
behaviors, or phenomena
within a specific population or
setting.
Descriptive Study
Analyzes relationships
between variables using
statistical techniques.
Descriptive Study and Observational Study
Experience of a group of patients with a similar diagnosis
Case Series
A case series typically involves a group of patients who have been diagnosed
with the same or similar medical condition.
Case Series
Cases may be identified from a single or multiple sources
Case Series
Cases for a case series can be identified from various sources, including a
single hospital or clinic, multiple healthcare facilities, or population-based
registries.
Case Series
Generally report on new/unique condition
Case Series
Case Series is useful for hypothesis generation T/F
T
Case Report is Informative for very rare disease with few established risk factors T/F
F. Case Series is informative…
Disadvantage of case series is it cannot study cause and effect relationships T/F
T
Case series can assess disease frequency T/F
F. cannot assess
one cause of unusual findings
Case report
2 descriptive studies
Case report
Case series
involves the detailed description of a single patient or a small group of patients
who present with an unusual or rare medical condition, complication, or
unexpected response to treatment.
case report
multiple cases of findings
Case series
*involves the analysis and description of a group of patients who share similar
clinical characteristics, diagnoses, or experiences.
Case series
Basic question in analytical study:
ARE EXPOSURE AND DISEASE LINKED?
relationship between exposure and disease:
E –> D; Exposure leads to disease
Group data
Ecological Study
Individual data
Cross-sectional study
Case-control study
Cohort study
An investigation of the distribution of health and its determinants between groups
of individuals.
Ecological study
Unit of study is the aggregate data not individual level
Ecological study
- It is usually be conducted as the first step study for research
Ecological data
The result is difficult to interpret because of confounding and bias
Ecological data
Advantage of Ecological data is it is cheap, quick and convenient since is
usually comes from existing data . T/F
True
Ecological data is unable to link exposure with diseasein individual (ecological fallacy) T/F
T
A disadvantage of ecological data is its limit to control effect of other factors. T/F
True
An observational design that surveys exposures and disease status at a single point of a time (a cross section of the population)
Cross Sectional Study
Often used to study conditions that are relatively frequent with long duration of
expressions (nonfatal, chronic conditions)
Cross-sectional Study
It measures prevalence, not incidence of disease
Cross-sectional Study
- Not suitable for studying rare or highly fatal diseases or a disease with short
duration of expression
Cross-sectional Study
CROSS-SECTIONAL STUDY Gives general description or scope of problem, T/F
T
Cross-sectional study is useful in health service evaluation and planning. T/F
T
Cross sectional study is the baseline for retrospective study. T/F
F. baseline for prospective study
Cross-sectional study advantage is that it is low cost. T/F
T
A disadvantage of cross-sectional study is that there is no calculation of risk. T/F
T
A disadvantage of cross-sectional study is that temporal sequence is unclear. T/F
T
A disadvantage of cross-sectional study is that it is good for rare disease. T/F
false. It is NOT good
A disadvantage of cross-sectional study is that selective recall can lead to bias. T/F
T
An “observational” design comparing exposures in diseases cases vs healthy
controls from same population
Case Control Study
Exposure data collected retrospectively
Case control study
Most feasible design where disease outcomes are rare
Case Control Study
The ODDS ratio
Odds ratio = ad/bc
An advantage of case control study is that it is Cheap, easy and quick studies. T/F
True
An advantage of case control study is that it Require comparatively few subjects. T/F
T
In case control studies, its advantage is that Multiple exposures can be examined.
T
In case control studies, rare diseases and diseases with long latency can be studied
True
A disadvantage in case control studies is that the Case and control selection are
troublesome. T/F
T
A disadvantage in case control studies is that it is subject to bias. T/F
T
In case control study, a disadvantage is that direct estimation of incidence is not
possible
T
In case control studies, if the incidence of exposure is low, it is difficult to show the difference between cases and controls, a disadvantage.
F. incidence of exposure is high
An “observational” design comparing individuals with a known risk factor or
exposure with others without the risk factor or exposure.
Cohort Study
Looking for a difference in the risk (incidence) of a disease over time.
Cohort Study
One of the best observational design
Cohort study
Data usually collected prospectively (some retrospective)
Cohort study
Cohort study advantage is that it can establish population-based incidence. T/F
T
In cohort study, there is an inaccurate relative risk (risk ratio) estimation. T/F
F. Accurate relative risk
In Cohort study an advantage is that it can be used where randomization is
not possible. T/F
T
In Cohort study, Selection and information biases are increased. T/F
F. Decreased
In Cohort study, multiple outcomes can be studied. T/F
T
A disadvantage of Cohort study is that it is lengthy and expensive. T/F
T
Cohort studies may require large samples. T/F
T
Cohort studies are not suitable for rare diseases. T/F
T
Cohort studies are not suitable for diseases with long-latency. T/F
T.
In cohort studies, unexpected environmental changes may influence the association. T/F
T
In Cohort studies, a disadvantage is nonresponse, migration and
loss-to-follow-up biases. T/F
T.
In this study, treatment and exposures occur in a “controlled” environment.
Experimental study.
In this study, there are Planned research designs.
Experimental study.
The most well known experimental designs
Clinical trials
In this study, Investigator can “control” the exposure to laboratory experiments except living populations are the subjects.
Experimental study.
This study generally involves random assignment to groups
Experimental study.
It is the ultimate step in testing casual hypothesis
Experimental study
The “gold standard” of research designs
Experimental study.
Provides most convincing evidence of relationship between exposure and effect
Experimental study.
An advantage of experimental study is its ability to randomize subjects. T/F
T.
An advantage of experimental study is the temporal sequence of cause and
effect. T/F
T.
An advantage of experimental study is it can control extraneous variables. T/F
T.
An advantage of experimental study is it is the best evidence of casuality. T/F
T.
One disadvantage of experimental study is that it is expensive.
T.
One disadvantage of experimental study is that it may be unethical to assign persons
to certain treatment or comparison
groups.
T.
A design with the subject randomly assigned to “treatment” and “comparison”
groups.
Randomized Clinical Trial
Provides most convincing evidence between exposure and effect
RCT
It is possible to use RCT’s to test effects of exposures that are expected to be
harmful for ethical reasons. T/F
F. It is NOT possible.
What are other types of Experimental study
Field trials
Community Trials
Animal studies
statistical analysis of a collection of studies
Meta analysis
Focus on contrasting and comparing results from different studies in anticipation of identifying consistent patterns and sources of
disagreements among these results.
Meta-analysis methods.
