Types of research Flashcards
what is EBM
evidence based medicine = using current best evidence to make core clinical decisions for individual pt
evidence is integrative and performance continually evaluated
clinical problem determines what evidence is used
who sets standards for research
research ethic approval
protects participants’ rights in animal/human research
when is ethic approval needed for research
if study involves animal/human participants
AND:
gathering new info OR creating knowledge that can be generalised beyond the pt sample
SUMMARY : if research - needs ethical approval, if health improvement study - no ethical approval
what do __ mean
exposure
outcome
prevalence
incidence
exposure - RF for disease
outcome - disease itself
prevalence - frequency of cases in a population at a given time
incidence - frequency of NEW cases in a population over a duration of time
prevalence = incidence x disease duration
incidence = no. new cases/ no. at risk (for a given time period)
prevalence = no. with disease/ no. at risk of disease
what are the different types of prevalence
point - prevalence at a particular time
period - over a duration of time
lifetime - at any point in their lifespan
period prevalence = all cases
incidence = NEW cases only
when is point/period + period/lifetime prevalence used
point = tracking changes, better pt recall
lifetime = if episodic, fluctuating, short condition
how is prevalence reported
based on exposure status
what are the different types of research studies
descriptive:
case report, cross-sectional
analytical:
observational - case control, cohort
experimental - RCT
what are pros + cons of cross-sectional study
pros:
compares prevalence in exposed/nonexposed group - used to initially inform for a hypothesis for future study
cheap, quick
cons:
not done if rare exposure/outcome
can’t separate cause (exposure) and effect (outcome)
cant measure rate of new cases rising
how do primary + secondary research differ
primary = collected by researcher (survey data)
more control over variables measured
but expensive + time-consuming
secondary = collected by someone’s for different purpose (hospital records, mortality register)
cheap, ethical approval not needed
poor accuracy - may miss data
what are pros + cons of cohort study
pros:
shows evidence of cause-effect (exposure-outcome) relationship as temporal precedence
can calculate incidence rate/risk
good if exposure is rare
cons:
expensive as large sample size and long duration (attrition can occur - people dropping out, so missing data)
confounding variables
not if outcome is rare
when is cohort + case-control study useful
cohort: if exposure rare + outcome common
case-control: if exposure common + outcome rare
what are pros + cons of case-control study
pros:
shows evidence for cause-effect
identifies multiple exposures
good if outcome is rare
cheap, short time scale
cons:
can’t calculate prevalence, incidence, RR
retrospective study, so data availability/quality is poor
not if rare exposure
what are pros + cons of RCT
pros:
best single study for causal association
provides evidence for safety + efficacy/effectiveness of intervention
reduces confounding variables
establishes temporal precedence
cons:
expensive, time consuming, laborious
internal validity issues - selection, observer/detection, performance, attrition biases
external validity issues - intervention not generalisable, pt group may be unrepresentative
what are pros + cons of systematic review/metanalysis
pros:
conclusions are more reliable/robust
core of EBM
cons:
limited availability/quality of evidence - necessary data may not be included
time consuming
requires expertise
