Week 2 - QUANTITATIVE Designs

Question 1

Types of Quantitative Research Designs

Answer 1

Descriptive studies
- most basic
- usually performed at the start of the research process
- CANNOT ESTABLISH CASUAL RELATIONSHIPS
TYPES: case report, case series

Observation studies
- data is collected from watching, good for describing the size of the disease and characteristics of the people sick
- CANNOT ACTIVELY INTERVENE
TYPES: cross sectional, case-control, cohort study,

Experimental studies
- clinical trials
TYPES: pre-post, quase-experimental, CCT, RCT

Question 2

Cross Sectional study

What is it, usefullness, strengths and weaknesses

Answer 2

WHAT: group of people observed at a particular time.

USEFUL FOR: Used to find a relationship/association between a risk factor/characteristic and a condition

STRENGTH:

• fast
• inexpensive
• no loss of follow up (attrition)
• helpful to determine PREVALENCE

WEAKNESS

• cannot determine causality
• can’t study rare outcomes

Question 3

Cast Control

What is it, usefulness, strengths and weaknesses

Answer 3

WHAT: you work backwards; there are 2 groups (one with disease and other no disease) then researcher works backwards to work out what is the difference

USEFUL FOR: It is useful to determine the strength of the association between each predictor variable and the presence of absence of disease

STRENGTH:

• inexpensive and efficient
• rare outcome
• established association
• *odds ratio is involved in this study as it is the measurement of association between exposure and outcome

WEAKNESS:
- causality difficult to establish

Question 4

Cohort studies

What is it, usefulness, strengths and weaknesses

Answer 4

WHAT: it is the best observational quantitative design
A cohort of people exposed to risk factors and it tracks them overtime.

USEFUL FOR: knowing if the predictor variable was present before the health outcome occurred. It directly measures incidence (risk of getting a disease over time) of a disease outcome.

STRENGTH:
- what it is useful for

WEAKNESS:

• expensive and inefficient
• need to follow up
• attrition reducing validity

Question 5

Pre-post study

What is it, strengths and weaknesses

Answer 5

WHAT: you have pre data from sample, expose them tot he intervention, then take data after from the sample.

STRENGTH:

• quick
• easy
• no expensive

WEAKNESS
- don’t know if the intervention was the reason for the post data

Question 6

Quasi-experimental

What is it, strengths and weaknesses

Answer 6

WHAT: same as pre-post study however there are 2 groups (controlled and intervention) then compare both groups to find conclusions.

WEAKNESS:
- the measurement of these two group is not at the same time (compared over different time periods), seasons can affect arthritis.

Question 7

Controlled clinical Trial (CCT)

What is it, strengths and weaknesses

Answer 7

WHAT: same as quasi-experimental but the measurement is at the same time

WEAKNESS: there is no randomness of allocation between groups, the researcher could deliberately fudge the groups (make them uneven/dodgy) to get the desired results.

Question 8

RandomIsed Control Trial (RCT)

What is it, strengths and weaknesses

Answer 8

WHAT: is the best one! same as CCT however the groups are randomly allocated

WEAKNESS:
- expensive

Subtypes of RCT

• cluster RCT (group randomisation/clusters are schools or cities)
• step wedged design (individual receives intervention in each time period)