Key Concepts and Design

Question 1

Define epidemiology

Answer 1

the study of the distribution and determinants of health related states (health related outcomes) or events in specified populations

Question 2

what is distribution made up of in epidemiology

Answer 2

count, rate, risk - how many

Question 3

what are the determinants in epidemiology

Answer 3

chemical, biological, physical, behavioural, social - what is the cause

Question 4

what does exposure mean in epidemiology

Answer 4

a potential cause, ie disease or genetic such as ethnicity

Question 5

describe the steps in the process of a scientific method

Answer 5

observations
propose a hypothesis / modify a hypothesis
test hypothesis
reject or not reject

Question 6

what happens in the continuous process of testing if you can reject the hypothesis

Answer 6

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

Question 7

what is evidence based medicine

Answer 7

The conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients…”

Question 8

what are the 4 types of evidence

Answer 8

description - what happened
prediction - what will happen
casual inference - if we change X how would that change y
qualitative - what why how should

Question 9

what are deterministic events vs probabilistic event

Answer 9

outcome determined (eg bacteria causes specific disease)

outcome based on probability eg living to 100

Question 10

what is the difference between population research and clinical research

Answer 10

pop - focused on helping populations

clinical - focus on helping the individual

Question 11

define these terms:
population
census
population based study

Answer 11

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

Question 12

what is a case report

Answer 12

describes one case but if the event is probabilistic it can’t be used to makes inference or predictions

Question 13

what is a case series

Answer 13

describes multiples cases of same disease to make predictions ad inferences

Question 14

what are register based studies

Answer 14

case series in a population more likely to have similar determinants

Question 15

what are cross sectional studies

Answer 15

study of a group at a single point in time - data can be gathered or directly measured

Question 16

what are cohort studies

Answer 16

examine a group of people over time - present multiple results allowing a variety of hypothesis

Question 17

what are ecological studies

Answer 17

a study that examines aviations between geographic areas - the units of analysis are not individuals but areas

Question 18

what is a case control study

Answer 18

select a group with/out ideas and examine their history

Question 19

what is validity

Answer 19

does it measure accurately what it is supposed to measure

Question 20

what are the three types of validity

Answer 20

construct
content
face

Question 21

what is construct validity broken up into and what do they mean

Answer 21

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

Question 22

what is content validity

Answer 22

the outcome measures all facets of a given construct eg depression outcome should include both affective and behavioural symptoms

Question 23

what is face validity

Answer 23

the outcome appears to measure what is should measure eg measuring obesity - weight, clothes sizes, BMI, waaist to height ratio

Question 24

what is reliability and its two sub types

Answer 24

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

Question 25

what is responsiveness

Answer 25

the outcome should be able to detect real changes when they occur - is the outcome sensitive enough (within the population)

Question 26

what are the uses of health outcomes

Answer 26

clinical treatment / trials

identify national and international variation - promote equality

Question 27

what are some common issues with health outcomes

Answer 27

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