Quantitative 2- Randomised Control Trials Flashcards
What is the underlying theory of experimental methods of RCT’s?
Positivism
What does experimental methods involve?
Active manipulation of variables under the control of the researcher and attempt to study how participants will react to the manipulated conditions through monitoring one or more outcome measures.
What does experimental methods attempt in doing?
Attempts to establish laws and principles by developing hypothesis that can be accepted or rejected through structured tests under controlled conditions.
What is the definition of experimental design?
a formal, systematic process in which numerical data are utilised to obtain information about the world. Also, to describe, test relationships and examine cause and effect.
Experimental design are often boasted to be..
the gold standard and the most rigorous
What are randomised control trials also called?
Randomised clinical trials
Controlled clinical trials
Why do RCT’s follow very strict procedures?
Follow very strict procedures to make the process transparent because they are used in healthcare to test treatment or interventions on people or patients.
How are hypothesis established?
Making a statement that predicts a direct relationship between a cause and its effect.
In an experiment it is the researcher’s job to rule out possible causes leaving only the most plausible explanation remaining- trying to isolate the cause and ruling out any other
What is a null hypothesis?
It is usual to propose a further hypothesis at the same time, one which stated the opposite position to the original.
First hypothesis is labelled H1 and the null hypothesis is labelled H0.
What happens after the hypothesis is established?
Population and sampling
Finding participants who are eligible for the experiment
The participant need to exhibit the same characteristics
Called the study population
Specifying eligibility criteria for inclusion in the study
Randomly sampling from the study population
What is the eligibility criteria?
Potential inclusion of all those people who might have the characteristics needed for the study.
- Often easier to state who is excluded first.
- Might want to limit the age range
- Should have a clear explanation of why the particular criteria has been selected.
- Recruitment should be conducted using the principle of informed consent.
What is random sampling?
Method of picking a sample from the study population where everyone has an equal chance of being chosen.
What is a sample size?
Optimum number of participants
Too many- participants are burdened unnecessarily.
Sample size calculation needs to be made based on the individual feature of the study.
What is random assignment?
Assignment of the participants to receive either the new treatment or the placebo.
The purpose: create two groups that are characteristically equal at the baseline.
What is concealment?
Blind studies are important to decrease biasness
Controversy about the placebo effect- the idea that people getting the placebo demonstrate relief of symptoms.
RCT need to report the process of concealment .
What is double blinding?
Where two parties are unaware of the treatment allocated to the participants.
What are the different forms of data?
- Structured observations
- Questionnaires
What is intention to treat analysis (ITT)?
All data are analysed according to the trial protocol and the groups to which they were randomly assigned, regardless of their adherence to the entry criteria and the treatment they actually received and regardless of subsequent withdrawals from treatment or deviation from the protocol.
Avoids over-optimistic estimates.
What are the different types of bias?
Selection bias Allocation bias Detection bias Observational bias Attrition bias Confounding bias Recall bias Publication bias
What is selection bias?
systematic difference between those selected into the sample and those not selected. Therefore, not a representative.
What is allocation bias?
a systematic distortion of the data as a result of the way in which participants were allocated to the experimental or control group.
What id detection bias?
differences in the assessment of the outcome between the experimental and control group.
What is observational bias?
contaminated observations by the observer’s belief, prejudice or background assumptions
What is attrition bias?
systematic difference in the loss of participants from the experimental and control group.
