1st exam Flashcards
Case control study:
a study design that examines a group of people who have experienced an event (usually an adverse event) and a group of people who have not experienced the same event, and looks at how exposure to suspect (usually noxious) agents differed between the two groups. This type of study design is most useful for trying to ascertain the cause of rare events, such as rare cancers.
Cohort Study:
a non-experimental study design that follows a group of people (a cohort), and then looks at how events differ among people within the group. A study that examines a cohort, which differs in respect to exposure to some suspected risk factor (e.g. smoking), is useful for trying to ascertain whether exposure is likely to cause specified events (e.g. lung cancer).
Randomized Controlled Trial:
a trial in which participants are randomly assigned to two or more groups: at least one (the experimental group) receiving an intervention that is being tested and another (the comparison or control group) receiving an alternative treatment or placebo. This design allows assessment of the relative effects of interventions.
Meta-analysis:
A statistical technique that summarizes the results of several studies in a single weighted estimate, in which more weight is given to results of studies with more events and sometimes to studies of higher quality.
Systematic Review:
a review in which specified and appropriate methods have been used to identify, appraise, and summarise studies addressing a defined question. It can, but need not, involve meta-analysis). In Clinical Evidence, the term systematic review refers to a systematic review of RCTs unless specified otherwise.
A Scientific Theory
A scientifically accepted general principle supported by a substantial body of evidence put forth to provide explanation of observed facts.
Retrospective:
information that has already been collected.
Qualitative
Approach
Qualitative
Assumes truth is subjective and relative to interpretation by the individual.
Data is captured in words from which patterns or themes are discerned.
Design format
Degree to which the investigator actively intervenes with the subjects
Experimental – randomization, intervention group, control group, high control
Quasi-experimental – an intervention but missing randomization or control group; overall a lower level of control.
Non-experimental – observational, report what is found; no intervention
Cross-sectional:
the question can be addressed by using information collected on subjects at a single point in time.
Longitudinal:
more than one measure taken over multiple time points.
Retrospective:
information that has already been collected.
Prospective:
information collected going forward.
Diagnostic Tests
Non-experimental and cross sectional.
Determines usefulness of test in correctly identifying a pathology or impairment.
Random assignment is not a priority since subject must have the condition under study.
Strongest design: individuals who appear to have condition are evaluated with the test as well as with a second test of which has been established as “Gold standard”.
Prognostic
Prospective/retrospective cohort or case control
Assess relationship between a factor and outcome
Non-experimental, but control through statistical adjustment
Cause & Effect between factors and outcomes cannot be established, only inferred, if:
Factor preceded the outcome (longitudinal design)
Relationship between factor/outcome strong
Findings consistent with previous studies
Clinical Measures
Development of new or modification of existing measurement instruments
Nonexperimental
Often cross-sectional but can be longitudinal if objective is to detect change over time
Repeated administrations determine reliability
Comparison to a superior instrument determine validity
Interventions
Used to determine benefit/harm
Efficacy: desired outcome under ideal conditions
Effectiveness: desired outcome under clinical conditions
Treatment needs to clearly precede the outcome
Experimental & Quasi Experimental designs
Efficacy study:
measuring the extent to which an intervention produces a desired outcome under ideal conditions
Effectiveness study:
measuring the impact of an intervention under usual clinical conditions
Outcomes Research
Focuses on the impact of clinical practice in the real world, i.e., end results of care
Nonexperimental designs, primarily observational format with less control features
Results reflect real-world conditions with confounding conditions
Used as basis for assessing quality of care across settings and disciplines
Frequently retrospective in approach, may be cross-sectional or longitudinal
Multiple groups with differing characteristics can be used
Self-reported outcome measures are used for studies about disability, health status, satisfaction, or quality of life
Primary data
is collected from subjects in real-time
Secondary data
is collected during routine business or a prior research activity
Power
is the probability that a statistical test will identify a relationship or difference
Components of the Research Article
Introduction
Methods
Results
Discussion
Introduction
Background/brief lit review
Purpose statement /Hypothesis
Methods
Subjects Study Design Variables Techniques/methods Statistical analyses
Results
Results and only results
Discussion
Highlight main findings
Discuss how data fits in literature
Summary and Conclusion including clinical implications
Null hypotheses
are predictions that no difference or relationship between variables will be demonstrated based on the research intervention.
Research hypotheses
are predictions of what the investigator thinks will happen or what the relationship between x and y is.
Impact factor
a measure of the frequency with which the “average article” in a journal has been cited in a given period of time.
Variables
Characteristic of an individual, object, or environmental situation that may take on different values:
