Week 3

Question 1

Define observational studies

Answer 1

A study that is done where a particular trend or concept is observved

Question 2

Define experimental studies

Answer 2

Experimental studies are ones where researchers introduce an intervention and study the effects.

Question 3

3 types of research

Answer 3

Descriptive
Relational
Causal

Question 4

Hierarchy of evidence (1 - 7)

Answer 4

1. Background info (Lowest, weakest, worst)
   
   2. Case - controlled studies / Reports
   3. Cohort studies
   4. Randomised controlled trials (RCTs)
   5. Critically - appraised individual articles
   6. Critically - appraised topics
   7. Systematic reviews

Question 5

Define cross - sectional study

Answer 5

collect data from many different individuals at a single point in time

Question 6

Advantages and disadvantages of cross - sectional studies

Answer 6

Advantages

- More time - efficent 
- Often less expensive 
- Reduced likelihood of attrition 

Disadvantages

- Less powerful (within group variance is higher)
- 'Cohort problem". E.g. assessing physical activity participation but neglecting to recognise that school PE changes over the years

Question 7

Define case-control study

Answer 7

A study that compares two groups of people: those with the disease or condition under study (cases) and a very similar group of people who do not have the disease or condition

Question 8

Define cohort study

Answer 8

A study design where one or more samples (called cohorts) are observed over a period of time. The incidence of disease in the exposed group is compared with the incidence of disease in the unexposed group.

Question 9

Cohort study advantages and disadvantages

Answer 9

Advantages

- Potentially very rich data set 
- Same people are measured, so minimises the effect of other variables 

Disadvantages

- Drop out, mortality
- Non - equivalence of those who dropped out and those who remained in the study. E.g. may no longer representative of the target population 
- Familiarity with the experiment. E.g. responses over time may be influenced by previous tests

Question 10

What are the 4 types of observation studies

Answer 10

Cohort
case studies
cross-sectional
case-control

Question 11

What are the 3 experimental study types

Answer 11

Single group interventions
Quasi - experimental
Randomised controlled trials

Question 12

Define single group interventions

Answer 12

• Take a group of people, intervene

Measurements at baseline and follow - up (s)

Question 13

Define quasi - experimental study

Answer 13

• Measures are completed in an intervention and comparison group with similar characteristics
  
  • Group are not randomised

Question 14

Quasi - experimental advantages and disadvantages

Answer 14

Advantages

- Useful when randomisation is difficult 
- Can save time and resources 
- Maybe a reasonable alternative to RCT 

Disadvantages

- Groups may differ, introducing bias
- Need to document characteristics 
- Need to acknowledge potential bias 
- Weakens potentional casual effects

Question 15

Define randomised controlled trials

Answer 15

• Controlled
  
  • Random allocation to groups
    Pre and post measures

Question 16

Define systematic review

Answer 16

A systematic review is a review of a clearly formulated question that uses systematic and reproducible methods to identify, select and critically appraise all relevant research

Question 17

Why do a systematic review

Answer 17

• Present the evidence base in an accessible format. Helping readers find the results of research quickly and to assess the validity, applicability and implications of those results
  
  • Provide more reliable findings from which conclusions can be drawn and decisions made
  • The needs of healthcare providers, consumers, researchers, and policy makers