Key Concepts and Design Flashcards
Define epidemiology
the study of the distribution and determinants of health related states (health related outcomes) or events in specified populations
what is distribution made up of in epidemiology
count, rate, risk - how many
what are the determinants in epidemiology
chemical, biological, physical, behavioural, social - what is the cause
what does exposure mean in epidemiology
a potential cause, ie disease or genetic such as ethnicity
describe the steps in the process of a scientific method
observations
propose a hypothesis / modify a hypothesis
test hypothesis
reject or not reject
what happens in the continuous process of testing if you can reject the hypothesis
if you can’t reject the hypothesis you keep testing until you can in which case you modify the hypothesis and test a new one
what is evidence based medicine
The conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients…”
what are the 4 types of evidence
description - what happened
prediction - what will happen
casual inference - if we change X how would that change y
qualitative - what why how should
what are deterministic events vs probabilistic event
outcome determined (eg bacteria causes specific disease)
outcome based on probability eg living to 100
what is the difference between population research and clinical research
pop - focused on helping populations
clinical - focus on helping the individual
define these terms:
population
census
population based study
the universe from which a sample is drawn
if the sample is the total population
if the study population is the total population of a country or area
what is a case report
describes one case but if the event is probabilistic it can’t be used to makes inference or predictions
what is a case series
describes multiples cases of same disease to make predictions ad inferences
what are register based studies
case series in a population more likely to have similar determinants
what are cross sectional studies
study of a group at a single point in time - data can be gathered or directly measured
what are cohort studies
examine a group of people over time - present multiple results allowing a variety of hypothesis
what are ecological studies
a study that examines aviations between geographic areas - the units of analysis are not individuals but areas
what is a case control study
select a group with/out ideas and examine their history
what is validity
does it measure accurately what it is supposed to measure
what are the three types of validity
construct
content
face
what is construct validity broken up into and what do they mean
convergent - are constructs that should be related eg physical functioning
discriminate - it doesn’t measure what it should eg - fear of cancer recurrence does not equal psychological stress which does not equal health related quality of life although these concepts are related
what is content validity
the outcome measures all facets of a given construct eg depression outcome should include both affective and behavioural symptoms
what is face validity
the outcome appears to measure what is should measure eg measuring obesity - weight, clothes sizes, BMI, waaist to height ratio
what is reliability and its two sub types
consistency of the measurement
test-retest reliability - are measurements consistent over time if nothing has changed
inter-rater reliability - do different assessors give the same result
what is responsiveness
the outcome should be able to detect real changes when they occur - is the outcome sensitive enough (within the population)
what are the uses of health outcomes
clinical treatment / trials
identify national and international variation - promote equality
what are some common issues with health outcomes
selection bias - overrepresentation of good patients in trials
timing of assessments
missing data - major issue, but unavoidable, missing at random, data imputation
response shift - value hat people attribute
differential item functioning - language, culture, country, age, gender
