BIOL 437 Week Three Flashcards
study design
- program that directs the researcher along the path of systematically collecting, analyzing and intrepreting data
- allows for descriptive assessment of events and for statistical inference
study types
-experimental
-observational
>descriptive
>analytic
descriptive epidemiology
- examining the distribution of disease in a population
- observing the basic features of it’s distribution
- when, where, who
analytic epidemiology
- testing a hypothesis about the cause of disease by studying how exposures relate to the disease
- observational or experimental
analytic epi-studies require info to
- know where to look
- know what to control for
- develop viable hypotheses
analytic epi- is built around
-the analysis of the relationship between two items
>exposures
>effects (disease)
-looking for determinants or possibe causes of disease
-useful for hypthesis testing
descriptive statistics
-can take on various forms >tables >graphs >numerical summary measures -application of statistical methods makes it possible to effectively describe the public health problem
helpfulness of descriptive epidemiology
- info about a disease
- clues to identify a new disease
- identifies the extent of the public health problem
- obtains a description of the problem that can be easily communicated
- identifies the population at greatest risk
- assists in planning and resource allocation
- identifies avenues for future research
4 types of descriptive studies
- Ecologic studies: population level
- Case reports
- Case series
- Cross-sectional surveys
ecological study
-involves aggregated data on the population level
-ecological fallacy
>when population level are used for individual level
-advantage: annoymous
-disadvantage: can’t have individual correlation
case report
-involves a profile of a single individual
case series
-involves a small group of patients with a similar diagnosis
-provide evidence for longer scale studies
>hypotheis gathering
cross-sectional survey
- prevelance survey
- short period of time
- no follow-up
- all variables measured at a point in time
- no distinction between potential risk factors and outcomes
- good for examining associations between factors
strengths of cross-sectional
- several associations at once
- relatively inexpensive
- short period of time
- control
- biases due to observation and loss to follow up does not exist
weakness of cross-sectional
-unable to establish sequence of events >association NOT causation -influenced by response bias -no follow-up -no incidence or relative risk data
serial surveys
-cross-sectional surveys that are routinely conducted
>regular frequencies
cohort study
-of persons who have been exposed and are followed over time with selected health outcomes
case-control study
-of persons who have been exposed and are followed over time with selected health outcomes