experimental studies Flashcards
List the 4 types of quantitative research questions are there ?
1) therapy questions
2) prognosis questions
3) etiology questions
4) descriptive
What type of quantitative research questions are used for experimental studies?
1) therapy
2) prognosis
What type of quantitative research questions are used for quasi- experimental studies?
Therapy questions
What type of quantitative research questions are used for non experimental studies?
1) prognosis
2) etiology
3) descriptive
What is the difference between experimental and non experimental study designs?
Experimental study designs usually involve intervention - an independent variables
What is longitudinal design
Collect data of same subjects in multiple time points over an extended period
Appropriate to study outcome variables changing over time
Strengthen causal inference with multiple time-point data collection (cause and effect)
→ more likely a follow-up study
What is cross sectional design?
Collect data at one point / multiple times in a snapshot of time
Appropriate for describing phenomena at a fixed point (eg. physiological and psychological symptoms in menopausal women)
Can be used in retrospective design → collect data on independent and outcome variable at the same time
Can be used for time-related phenomena; but less persuasive than longitudinal design
What is experimental designs?
RCT - randomised controlled trials
What are the 6 features of a Experimental design?
1) intervention
2) control
3) randomisation
4) posttest
5) pre test
6) blinding
5 and 6 are optional
What is allocation concealment?
It is used during recruitment.
Concealing information regarding which patient is to be assigned to which group (ie sequence of random allocation)
Avoid doctor / researcher knowing the allocation; and then assigning inferior subjects to a particular group (detection bias)
What is blinding?
It is used during intervention
Not letting patients know which group they are allocated (eg placebo)
Reduces influences of patient knowledge on outcome (especially subjective outcomes)
why are allocation concealment and blinding important?
to reduce/prevent the bias in implementing/ carrying out the
experiment
Name the 5 types of experimental study designs
1) pretest-posttest control group design
2) pretest posttest control group design with repeated measures
3) crossover group design
4) post test only control group design
5) Solomon 4 group design
what is crossover design?
involves exposing the subjects to
more than 1 treatment group,
Subjects initially in the experimental group will receive the
treatment in the control group whilst
Subjects initially in the control group will receive the
treatment in the experimental group
* Wash-out period is necessary before the cross-over to
remove the carry-over effect
advantages of crossover design
The influence of confounding covariates is reduced because
each crossover patient serves as his or her own control.
statistically efficient
require fewer subjects than non-crossover designs
When should posttest only control group design be used
1) impossible to get pretest measurements
2) Pretest sensitization problem – may have
sensitized the subjects so that they respond
differently to the treatment (e.g. Education program
for improving spelling errors)
- Limited resources in collecting a pre-test measurement
what is solomon 4 group design ?
a combined design based
on Pretest Posttest Control Group Design and Posttest
Control Group Design.
It has the advantage of Pretest-Posttest Control Group
design and can further examine if Pretest has effect
what is single blinding?
patients are blinded but researchers are aware
what is double blinding?
both patients and researchers are blinded
