Collecting data

Question 1

Why compare the health of groups?

Answer 1

Research questions such as:

oIs this disease increasing in prevalence?

oDoes it occur with undue frequency in my local community?

oIs incidence associated with some suspected risk factor?

oHas the outcome changed since control measures were instituted?

-Differences between groups at a point in time / Differences between groups over time

Question 2

Cross-sectional study

Answer 2

one group surveyed to test associations between exposures and outcome/s

Question 3

Ecological study

Answer 3

ocommunity/population observed to test associations between exposures and outcome/s. the same as cross-sectional study.,

Question 4

Difference between Cross-sectional study and Ecological study

Answer 4

-Both studies focus on simultaneous observation of exposure and outcome, but the difference is the unit of observation.

oCross-sectional study – focuses on individual level data (a person)

oEcological study – focus on population-level data (could be a small community or a house)

Question 5

Cohort study

Answer 5

• You have disease-free participants followed up to see if they develop a disease (condition/outcome) of interest.
• Usually with groups who differ at outset on some exposure/s of interest
• whatever you are looking for, you want to recruit people that are frr of that condition at the beginning, then follow them up.
• the cohort study will have 2 groups- people who have the risk of the condition of study and people who do not (eg different age group)

Question 6

Case–control study

Answer 6

• groups who differ at outset on disease (condition/outcome) status
• Look back at exposure/s of interest
• this is different from the cohort study because you involve both the people that already have the disease and does that hasn’t in this one and then you look back in time to see if they have experienced some exposure in the past.

Question 7

Randomised controlled trial (RCT)

Answer 7

-groups who are randomly allocated to receive intervention/s versus comparator/s

oTest safety and efficacy/effectiveness of interventions

• The RCT is not an observational study, it is experimental. the other ones we’ve discussed are observational studies and in observational studies, the researchers do not manipulate the results in any way.
• in experimental studies, the researchers can actually manipulate the research and change something happening to people that they are using in the research, the allocate groups of people to receive and intervention vs some sort of comparator.
• RCT are used to test for safety and the efficacy or effectiveness of interventions.

Question 8

Case-control studies

Answer 8

It focuses on identifying group who differ based one whether they have the disease outcome of interest or not.