WEEK 3 Flashcards
1
Q
Exposure Measurement
A
- Available Dose
- Administered Dose (amount that has come in contact)
- Absorbed Dose (amount that enters the body)
- Active Dose (biologically effective, and targets the organ)
2
Q
Threats to validity
A
- confounding
- bias
- chance
3
Q
Random Error
A
- error due to chance
4
Q
Systematic Error
A
- error with a defined and predictable source
- consistently skews results to either under or overestimate them
5
Q
Is it possible to have both random + systematic error?
A
yes
6
Q
Reliability
A
- measurement tool with precision.
7
Q
Validity
A
- measurement tool with accuracy.
8
Q
Why do we get skewed results?
A
- measurement tools are not precise enough.
- 2 independent interviewers rank the same person differently using the same scale
- same interviewer ranks the same person differently twice
9
Q
Sources of Measurement error?
A
- Interviewer/observer
- records a random error
- biased over or underestimation
- Participant
- recall
- random/systematic error
10
Q
Reducing measurement error?
A
- once it has occurred, little or nothing can be done
- must be avoided through careful study design
clear measurements, pilot tests, and validation - appropriate measuring tool choice
- measurement error can not be controlled in the analysis.
11
Q
Methods of Measurement
A
- ratio: numerator not included in the denominator.
- proportion: numerator over total (numerator is included in the denominator)
- odd: the probability of occurrence (numerator / denominator - numerator)
- rate: speed of something (number of events / total population during the same time period)
12
Q
Measures of Health
A
- prevalence: amount of something in the population
- point PR + period PR (Same thing but period is over a time period and point is at a specific time) (# of cases / total population)
- incidence: number of new cases
- (# of new cases / population still at risk)
13
Q
What is the difference between prevalence and incidence?
A
- prevalence (what is already there)
- incidence (what is new)
14
Q
Measures of Association
A
- relative risk: measures strength of association…what is the likelihood that exposed will get the disease v. not exposed (a/a+b / c/c+d)
- odd ratio: odds of occurrence
(a/b / c/d) - odds of disease occurring in exposed / odds of disease occurring in unexposed.
15
Q
What measurement should you use for longitudinal studies?
A
- incidence
