RCT (Outcomes)

Question 1

Why do we need outcomes in trail

Answer 1

An appropriate outcome must be decided upon before the start of the trail in order to determine if the intervention and outcome has a causal relationship.

Question 2

What is the primary outcome?

Answer 2

The main outcome of the study

Question 3

What is the secondary outcome?

Answer 3

Any other outcomes of the study that isn’t the primary study

Question 4

What are the 5 criterias that outcomes should meet?

Answer 4

1) Clinically meaningful
2) Mesureable
3) Responsive
4) Reliable
5) Valid

Question 5

What does it mean when an outcome is clinically meaningful?

Answer 5

The outcome is of significant importance for the patient group studied.

Question 6

What does it mean when an outcome is measureable?

Answer 6

The outcome for both the intervention group and the control group should be able to be measured in order to compare the outcomes and detect any differences

Question 7

What does it mean when an outcome is responsive?

Answer 7

The measurement for the outcome should be able to detect any changes in the trial

Question 8

What does it mean when an outcome is reliable?

Answer 8

If the trail was to take place again on multiple occasions, would the outcomes of the trail be consistent

Question 9

What does it mean when an outcome is valid?

Answer 9

The measurement tool for the outcome should actual measure what you want it to measure

Question 10

What is internal validity?

Answer 10

Internal validity is concerned with whether the results of the study (the differences in the outcomes between the trial arms) are legitimate. If so, then a casual relationship between the IV and DV can be shown.

Question 11

What are the 6 main treats to internal validity?

Answer 11

1) History
2) Maturation
3) Testing effects
4) Instrumentation
5) Mortality
6) Selection Bias

Question 12

What is meant by a ‘History’ threat to internal validity?

Answer 12

Any events that are happening outside of the trial that affect the participants responses to the trial (e.g. media campaigns)

Question 13

What is meant by a ‘maturation’ threat to internal validity?

Answer 13

(more likely to be affect trails that take a long time) Any natural changes that occur over time to the participants, in which affects the outcome other than the intervention

Question 14

What is meant by a ‘testing effects’ threat to internal validity?

Answer 14

If you were to test the same participants over and over again, they may remember the correct answers and realise what they are being tested for. Which leads to a bias outcome

Question 15

What is meant by ‘instrumentation’ threat to internal validity?

Answer 15

Whereby the instrument used to measure the outcomes changes the outcomes itself

Question 16

What is meant by ‘mortality’ threat to internal validity?

Answer 16

Whereby people drop out of the study which becomes a problem if more people drop out of one trail arm than the other

Question 17

What is meant by ‘selection bias’ threat to internal validity?

Answer 17

Whereby the people from the sample that agreed to participate in the the trial are different to those from the sample that declined the offer to participate in the study, in some unanticipated way.

Question 18

What is external validity?

Answer 18

(aka: generalisability)

Whereby the results from the trial can be transferred to other populations of interest

Question 19

What are the 4 threats to external validity?

Answer 19

1) Internal validity (if a trial doesn’t have internal validity then it can not have external validity)
2) Selection effects
3) Reactive (aka. Hawthorne effect)
4) Measurement effects

Question 20

What is meant by ‘selection effects’ threat to external validity?

Answer 20

Whereby the ideal sample can not be obtained from the target population and so results can’t be generalised to populations of interest

Question 21

What is meant by ‘reactive effects’ threat to external validity?

Answer 21

Whereby people change their behaviour in the study, and this change has nothing to do with the intervention

Question 22

What is meant by ‘measurement effects’ threat to external validity?

Answer 22

This is similar to the testing effect (threat to internal validity) - whereby the same participants are tested on multiple occasions. The participants are likely to know the correct answers. So, the intervention no longer causes the outcomes. So the outcome can not be generalised