Exam 2 : Lecture Cross Section Flashcards
Cross sectional study, is it interventional or observational?
Observational
What do cross section studies do?
Capture health/disease and exposure statuses at the SAME TIME
Cross-sectional studies is also known as ____________
Prevalence study
Cross sectional study acquires information about a population without regard to exposure. T or F
True
What is known as a “snap shot” in time?
Cross sectional study
Cross sectional studies seek association. T or F
True
Cross sectional studies are not generalizable. T or F
False, they are
Every element in the population has a known probability of being included in sample
Probability sample
Examples of probability samples
Simple Systematic Stratified simple Stratified disproportionate Multi stage Cluster multi-stage
Assign random numbers, then take randomly selected number to get desired sample size or
Assigne random numbers then sequentially list numbers and take desired sample size from top of listed numbers
Simple random sampling
Assign random numbers, then randomly sort here random numbers, then select highest (or lowest), then take every Nth number to get desired sample size
Systematic random sampling
Sampling frame by by desired characteristic, then use simple random sampling to select desired sample size
Stratifed simple
Utilize stratified simple random sampling when baseline population is not at the desired proportional percentages to referent population
Stratified sample weighted to return sample population back to baseline population
Stratifed disproportionate
Uses simple random sampling at multiple stages towards selection: Regions Cit blocks Clinic Individuals
Multistage random sampling
Random sampling but cluster together or selected for inclusion
ex: all clinics in zip code
All house holds in community
Cluster multi stage
Quasi-Systematic or Conveniece samples
Decide on what fraction of population is to be sampled and how they will be sampled
(Non probable!)
Ex: all persons whose last name begins with M-Z
What are the two common broad approaches to collection of study data?
Questionnaires/surveys
Physical assessment
Advantages of cross-sectional study?
Quicker and easier for researcher
Less expensive for researcher
Can be analyzed like a case-control or cohort
Useful for estimating prevalence
Useful for answering research questions about a myriad of exposures and disease
Disadvantages of cross sectional study?
Prevalent cases may represent survivors
Difficult to study diseases of low frequency
Unable to generate incidence rates
Problems in determine temporal relationship of presumed cause and effect
NHANES
National health and nutrition examination survey
NHIS
National health interview survey
NAMCS
National ambulatory medical care survey
NHCS
National hospital care survey
BRFSS
Behavioral risk factor surveillance system
