cross sectional and ecological studies

Question 1

2 types of study

Answer 1

descriptive- no hypothesis (eg proportion of obese people in pop.)
analytic- hypothesis driven, analyse associations (eg is proximity to fast food joints associated with obesity)

Question 2

CS

how is information collected

Answer 2

observational study, gather information once or at one time period (repeat studies may become longitudinal)
exposure and outcome measured simultaneously

Question 3

CS

what part of population is used

Answer 3

whole pop. or a representative sample with no follow ups

Question 4

CS

descriptive vs analytic

Answer 4

D- freq. or distribution of exposure at one point (generates hypotheses)
A- compare exposed and non exposed to examine association involves hypotheses testing to see if its significant

Question 5

CS

where is it used

Answer 5

health service planning resource allocation and monitoring population health

Question 6

CS disadvantages

Answer 6

can’t prove causation/correlation, not suitable for short, rare, highly fatal diseases, also can be subject to bias

Question 7

CS advantages

Answer 7

quick cheap easy, large pop., can study multiple exposures/outcomes simultaneously, good to measure prevalence

Question 8

CS

repeat studies

Answer 8

eg health surveys, can make time series

Question 9

E

observational

Answer 9

based on groups eg country regions or school

Question 10

E

what’s it used for

Answer 10

study occurrence in groups or associations of groups (eg GDP and diabetes)

Question 11

E

3 variables used to capture characteristics

Answer 11

aggregated - summarised individual data
environmental- physical environment eg temp./pollu.
global- everyone in group has same level of exposure eg presence of cycle paths

Question 12

E

descriptive vs analytic

Answer 12

D- hypothesis generating describes distribution and patterns of outcome
A- hypothesis testing examines relationship in different groups or population over time

Question 13

E

studies can be experimental but also susceptible to

Answer 13

ecological fallacy where incorrect inferences are made about individuals based on populations data

Question 14

E advantages

Answer 14

easy to use with data and quick and cheap, ideal for population metrics of health eg life expectancy

Question 15

E disadvantages

Answer 15

ecological fallacy and other bias, sometimes to standardisation to ensure accurate comparisons