2.1 EPI - Overview on Descriptive Studies Flashcards
Primary characteristic of a 5-Star Physician necessary for descriptive studies (one of the 5 stars), that states that “everything is evidence-based”.
Researcher
2 Approaches to Research and their subcategories
Observational: Descriptive and Analytical
Experimental: Clinical Trials, Field Trial, Community Trial
Types of Observational - Descriptive studies
1) Case Report
2) Case Series
3) Ecological
4) Cross-sectional
Types of Observational - Analytical studies
1) Cross-sectional
2) Case Control
3) Cohort
T/F: The lack of manipulation of the study factor by the investigator is characteristic of Observational studies
TRUE
T/F: A descriptive study is an inquiry into the nature of an unknown phenomenon or the occurrence of an event
TRUE
T/F: A descriptive study gives us the ability to explain relationships, as well as providing better understanding of the nature of the subject of the study
FALSE. Descriptive studies cannot explain relationships
T/F: A descriptive study helps in the formulation of a hypothesis, though it cannot test the hypothesis
TRUE
The aim of a descriptive study:
Infer to the reference population the findings from a sample
Define: prevalent studies
Studies that describe how many people have a particular disease, how many have died from it, etc.
T/F: A case report is a detailed report of the symptoms, signs, diagnosis, treatment, and follow-up of a group of carefully selected subjects
FALSE. A case report deals with an INDIVIDUAL patient
T/F: Case reports may describe either novel occurrences or rare cases.
TRUE
Identify at least 2 topics of focus of most case reports.
1) Identifying possible associations between diseases or symptoms.
2) Unexpected events in the course of observing a patient.
3) Possible pathogenesis of a disease.
4) Unique or rare features of a disease.
5) Unique therapeutic approaches.
Limitations of a case report.
There is no statistical analysis or comparative group.
T/F: Case reports may provide the 1st report of an unexpected event
TRUE
Define: “Creeping Eruption”
a serpiginous skin eruption - caused by burrowing larvae of animal hookworms
Identify Type of Descriptive Study: commonly used to report unusual, rare, or unexpected events
Case Report
Identify Type of Descriptive Study: medical research study that may be retrospective or proscpective
Case Series
Identify Type of Descriptive Study: contains a brief objective report of the clinical characteristic or outcome from a group of clinical subjects
Case Series
Identify Type of Descriptive Study: contains a brief objective report of the clinical characteristic or outcome from a single clinical subject or event.
Case Report
Define: case selection bias
Selection of individuals with unique characteristics, which limits findings to only be applicable to a small group and NOT the general population.
T/F: Case Series studies shows temporal relationships between events and outcomes.
FALSE. Case series studies cannot show temporal relationships
T/F: Case Series studies have the benefit of providing statistical validity applicable to the general population.
FALSE
T/F: Case Series studies require a large sample size (at least 100 cases)
FALSE. Requires around 10 cases, but may even be considered as a case series with a sample size of 4-5
T/F: Case Series studies are different from Case Reports in that Case Series have a control or comparison group.
FALSE. Neither Case Reports nor Case Series study designs have a control or comparison group.
Identify Type of Descriptive Study: variables are all measured at a single point in time, with no structural distinction between predictors (exposure) or outcomes
Cross-Sectional
Identify Type of Descriptive Study: makes no attempt to establish a temporal relationship
Cross-Sectional
Identify Type of Descriptive Study: when a change in one measured variable is noted with a change in another
Ecological
Fill-In the Blank: An Ecologic Study describes the _____ and _______ of correlation between variables
Magnitude; Direction
Type of Ecologic Study that use on-going surveillance or frequent cross-sectional studies to measure trends in disease rates over many years in a defined population.
Longitudinal Ecologic Study
T/F: An ecologic study is useful for suggesting hypotheses, but cannot be used to draw causal conclusions
TRUE
Type of Fallacy/Bias: a logical error in the interpretation of statistical data, whereby inferences about the nature of specific individuals are based solely upon aggregate statistics collected for the group to which those individuals belong
Ecological Fallacy
Type of Fallacy/Bias: individuals chosen possess unique characteristics, which limits findings to only be applicable to a small group and NOT the general population.
Case-Selection Bias
Type of Fallacy/Bias: assumes that individual members of a group have the average characteristics of the group at large
Ecological Fallacy
T/F: In an Ecologic Study, statistics that accurately describe group characteristics do not necessarily apply to individuals within that group.
TRUE
Type of Relationship: Increase in the value of one variable is associated with a decrease in the second variable
Negative Relationship
Type of Relationship: Increase in the value of one variable is associated with both increase and decrease in the second variable
Curvilinear Relationship
Type of Relationship: Increase in the value of one variable is associated with a increase in the second variable
Positive Relationship
Identify: In an ecologic study, it is computed to specify the nature of the relationship between variables after observations are collected.
Pearson correlational coefficient (r)
T/F: Pearson’s “r” measures the degree of correlation of 2 non-continuous variables in an interval scale
FALSE. Continuous variables
Range of values of Pearson’s “r” that indicates that there is little or no relationship
0.00-0.25
Range of values of Pearson’s “r” that indicates that there is good to excellent relationship
> 0.75
Range of values of Pearson’s “r” that indicates that there is a fair degree of relationship
0.26-0.50
Range of values of Pearson’s “r” that indicates that there is moderate to good relationship
0.51-0.75
In the example examining correlations between meteorological parameters and prostate cancer, the ecologic study found that the colder temperature and drier climate in a country had what type of relationship with incidence of prostate cancer.
Positive Relationship
Fill-In the Blank: Cross-sectional studies may involve the measurement of _____ exposure and/or ______ exposure.
Current; Historic
T/F: Cross-sectional studies are valuable in providing descriptive information about prevalence of a particular variable under study
TRUE
The 3 General Steps in doing a Cross-Sectional study.
1) Select a sample from the population.
2) Collect data using standardized data collection method.
3) Analyze the collected data
Strengths of a Cross-Sectional study.
1) It is quick, cheap, and easy
2) Can study multiple exposures and multiple diseases.
3) True rates are determined (prevalence)
T/F: Cross-sectional studies are impractical for rare cases
TRUE
T/F: Cross-sectional studies are useful for establishing causal relationships (allows us to answer the question of which came first)
FALSE. Cannot establish causal relationships since the variables were taken at one point in time.
A Pearson’s “r” value of >0.75 indicates:
Good to excellent relationship
A Pearson’s “r” value of 0.26-0.50 indicates:
Fair degree of relationship
A Pearson’s “r” value of 0.00-0.25 indicates:
Little or no relationship
A Pearson’s “r” value of 0.51-0.75 indicates:
Moderate to good relationship
In Descriptive Epidemiology, health outcomes are classifications according to these variables.
Person, Place, and Time
T/F: Descriptive Epidemiology refers to studies that are concerned with characterizing the amount and distribution of health and disease within a population.
TRUE
T/F: Studies in descriptive epidemiology are focused on the development of hypotheses, which set the stage for subsequent research.
TRUE
Bonus: Conrad’s Favorite Food
Peanut Butter
Bonus: Conrad’s Favorite Drink
Root Beer
