Exam 1 Study Guide Flashcards
What type of study uses measures that include: counts, proportions, rates, survival
Descriptive Study
What type of study describes or characterizes the distribution of a disease in a specified population during a defined time period?
Descriptive Study
The following strengths are characteristic of what kind of study:
- describes frequency and pattern of health related states or events
- provides critical information for research, prevention and policy
Descriptive Study
The following challenges are characteristic of what type of study?
- impossible to monitor everything ( cost, time)
Descriptive Study
What type of study relates two or more population based measures to examine possible correlates between exposure and disease occurrence?
Ecological Study
What type of study measures exposure and disease independently at the population level. ( not in the same individual). Correlation does not prove causation.
Ecological Studies
The following strengths are characteristic of what type of study?
- describes potentially useful correlations that may warrant further study (hypothesis generating)
Ecological Study
The following challenges are characteristic of what type of study?
- information not at the level of the individual
- ecological fallacy
- cannot demonstrate cause and effect
Ecological Study
What type of study:
- surveys a defined population, usually within a short period of time
- study sample is usually identified without consideration of the distribution of exposure or outcome of interest
- examines distribution of disease and exposure as ascertained in the cross sectional survey
Cross Sectional Study
The following strengths are characteristic of what type of study?
- can stimulate prevalence of disease and/or exposure as well as cross classifications. Estimate can be useful in healthcare planning and delivery
- can be suggestive of risk factors for disease that may warrant further study
Cross Sectional Study
The following challenges are characteristic of what kind of study?
- temporal relation between exposure and outcome is not known, thus can not demonstrate cause and effect
Cross Sectional Study
What type of study is characteristic of the following?
- experimental design: intervention is under the control of the investigator
- participants randomized to receive experimental intervention vs standard intervention (or placebo)
- monitor out come of interest over time
Randomized Controlled Trials
What type of study is characteristic of the following?
- experimental design similar to randomized clinical trial
- subjects are often non-diseased members of a target population and the intervention is often aimed at disease prevention
- unit of randomization is the community/group level (school,hospital,sports team) rather than individual level
Community Trials
What type of study is well suited for studying rare diseases?
Case Control Study
In what type of study are participants selected on the basis of thier disease status?
Case Control Study
What type of study is often used to identify factors that may contribute to a medical condition by comparing subjects who have that condition/disease (the “cases”) with patients who do not have the condition/disease but are otherwise similar (the “controls”).
Case Control Study
The following strengths are characteristic of what kind of study?
- timeliness
- relatively low cost (compared to cohort study)
- ability to study rare outcomes
Case Control Study
The following challenges are characteristic of what type of study?
- no direct measure of disease risk
- retrospective ascertainment of exposure
- selection of appropriate controls
- restricted to study of single out come
Case Control Study
What type of study is an analysis of risk factors and follows a group of people who do not have the disease, and uses correlations to determine the absolute risk of subject contraction.
Cohort Study
The following strengths are characteristic of what type of study?
- document exposure prior to disease occurrence
- direct measure of disease rates and risk
- opportunities to assess multiple outcomes
Cohort Study
The following challenges are characteristic of what type of study?
- long time frame (usually)
- cost (expensive)
- loss to follow up
- inefficient for uncommon diseases
Cohort Study
When an investigator documents but does not manipulate the exposure of interest the overall design is said to be what?
Observational
When the investigator manipulates or assigns the exposure of interest the overall design is said to be what?
Experimental/Interventional
What type of studies are considered to be observational?
Descriptive Ecological Cross Sectional Case Control Cohort
What type of studies are considered to be experimental/ interventional?
Randomized Controlled Trial
Field Trials
Community Trials
What term describes new cases of disease diagnosed in a defined population during a specified time period? Measures include counts, percentages, rates
Incidence
What term describes the total number of cases (new and existing) of disease present on a defined population during a specified time period or at a specific point in time? Measures include counts, percentages
Prevalence
What term describes deaths due to the disease of interest occurring in a defined population during a specified time period? Measures include counts, percentages, rates
Mortality
What are two strategies to minimize bias?
Randomization
Blinding
Participants assigned to study groups at random is know as what?
Randomization
The following purposes are characteristic of what?
- diminish the opportunity for “confounding” by equalizing the effects of extraneous variables between/among the study groups
- diminish the opportunity for selection bias
Randomization
Assignment of study group conducted without the knowledge of study participants and/or investigators is know as what?
Blinding
The following purposes are characteristic of what?
- minimize bias in ascertainment of outcomes
- minimize differential attrition of participants
Blinding
What scenario occurs when either study subjects or investigators do not know intervention status?
Single Blind
What scenario occurs when neither study subjects nor investigators know intervention status?
Double Blind
What is the primary measure of association that is derived from cohort studies?
Risk Ratio (RR) also known as Relative Risk
What is the primary measure of association that is derived from randomized controlled trials?
Risk Ratio (RR) also known as Relative Risk
What is the primary measure of association that is derived from case control studies?
Odds Ratio (OR) also known as Estimate of Relative Risk
Among those with the exposure of interest what term expresses the proportion of the disease that is due to exposure and could be prevented if the exposure was eliminated?
Attributable Risk Percent
(RR - 1)/RR multiplied by 100
(OR - 1)/OR multiplied by 100
Or
Risk in exposed - Risk in unexposed/Risk in exposed
In the entire population what term expresses the proportion of the disease that is due to the exposure and could be prevented if the exposure was eliminated?
Population Attributable Risk Percent
E(RR-1)/[1+ E(RR-1)]
E(OR-1)/[1+ E(OR-1)]
E = % exposed in total population
Or
Risk in entire population - Risk in unexposed/Risk in entire population
