Fall 2023 Flashcards
What is a natural disease?
The usual course of disease over time
Prognostic Factor
Something (environmental factor, personal characteristic, behavior) that can be used to estimate the chance of recovery or recurrence
Risk Factor
Something (environmental factor, personal characteristic, behavior) that increases the chance of developing a disease
Prospective Cohort Study
1- Identify Sample at Risk
2- Asses Risk Factors @ Interest
3- Measure who develops outcome/not
Incidence (rate of developing)
Risk Ratio
Retrospective Case-Control Study
1- Collect data/review chart or records to determine who had exposure/risk factor or not
2- Identify “Cases” and “Controls”
Prevalence
Odds Ratio
Prevalence
Number of people who have the outcome at a given point in time / # of people at risk at that point in time
Incidence
Number of new people who develop the outcome over a period of time / # at risk during that period
Risk Ratios // Relative Risk
Likelihood with which those that have the risk factor will develop the outcome compared to those that don’t have the risk factor (prospective)
Odds Ratios
Likelihood with which those who have a condition (or outcome) have been exposed to a risk factor compared to those who don’t have the condition (retrospective)
Relative Risk - Cross Tabulation
a/(a+b)
_______
d/(c+d)
Odds Ratio - Cross Tabulation
ad
___
bc
RR/OR > 1
RR/OR - 1 = __ * 100% =
___% increase in Risk/Odds
RR/OR < 1
1 - RR/OR = __ * 100% =
___% reduction in Risk/Odds
Rule with RR/OR Confidence Interval
If it includes 1, there is no significance
Unadjusted or Crude Odds Ratio
- 2x2 Table or Logistic Regression
- Accounts for One Relationship
- One Independent, One Dependent
Adjusted Odds Ratio
- Calculations using Logistic Regression
- Accounts for Multiple Variables that Might Affect Relationship
- Multiple Independent Variables
Internal Validity
Relationship between independent (intervention) and dependent (outcome) variable
Tight control of experiment leads to higher internal validity
Efficacy of Treatment
External Validity
Extent to which the independent (intervention) and dependent (outcome) can be generalized outside of the experiment
Tight control of experiment can decrease external validity
Effectiveness of Treatment
Efficacy
Benefit of an intervention in an experimental setting
-Control of many variables
Effectiveness
Benefit of an intervention in a real-world setting
-Less control of variables, bias
Threats to External Validity
Selection
Setting
History
Intervention/Protocol
Construct Validity
Statistical Inference
Estimating characteristics of a population (parameter) from sample data (statistics)
-Population aggregate of persons/objects/events that meet a specific criteria
Probability Sampling
Simple Random
Systemic
Cluster
Stratified Random (Proportional / Disproportional)
Non-Probability Sampling
Convenience (Consecutive / Volunteer)
Quota
Purposive