Quasi-Experimental Study
A Quasi-Experimental Study is an observational study where ...
- Context:
- It can range from being a Matched-Control Quasi-Experiment to being an Unmatched-Control Quasi-Experiment.
- Example(s):
- a Counterfactual Study.
- …
- Counter-Example(s):
- See: Natural Experiment, Quasi-Randomized Study.
References
2013
- http://en.wikipedia.org/wiki/Quasi-experiment
- A quasi-experiment is an empirical study used to estimate the causal impact of an intervention on its target population. Quasi-experimental research designs share many similarities with the traditional experimental design or randomized controlled trial, but they specifically lack the element of random assignment to treatment or control. Instead, quasi-experimental designs typically allow the researcher to control the assignment to the treatment condition, but using some criterion other than random assignment (e.g., an eligibility cutoff mark) .[1] In some cases, the researcher may have no control over assignment to treatment condition.
Quasi-experiments are subject to concerns regarding internal validity, because the treatment and control groups may not be comparable at baseline. With random assignment, study participants have the same chance of being assigned to the intervention group or the comparison group. As a result, the treatment group will be statistically identical to the control group, on both observed and unobserved characteristics, at baseline (provided that the study has adequate sample size). Any change in characteristics post-intervention is due, therefore, to the intervention alone. With quasi-experimental studies, it may not be possible to convincingly demonstrate a causal link between the treatment condition and observed outcomes. This is particularly true if there are confounding variables that cannot be controlled or accounted for.[2]
- A quasi-experiment is an empirical study used to estimate the causal impact of an intervention on its target population. Quasi-experimental research designs share many similarities with the traditional experimental design or randomized controlled trial, but they specifically lack the element of random assignment to treatment or control. Instead, quasi-experimental designs typically allow the researcher to control the assignment to the treatment condition, but using some criterion other than random assignment (e.g., an eligibility cutoff mark) .[1] In some cases, the researcher may have no control over assignment to treatment condition.
- ↑ Template:Cite doi
- ↑ Rossi, Peter Henry; Mark W. Lipsey, Howard E. Freeman (2004). Evaluation: A Systematic Approach (7th ed.). SAGE. pp. 237. ISBN 978-0-7619-0894-4.
2007
- (Parienti & Kuss, 2007) ⇒ Jean-Jacques Parienti, and Oliver Kuss. (2007). “Cluster-Crossover Design: A method for limiting clusters level effect in community-intervention studies.” In: Contemporary Clinical Trials, 28(3). doi:10.1016/j.cct.2006.10.004
- QUOTE: Quasi-experimental studies are defined as observational studies in which the study factor is manipulated without randomization [7]. Before–after studies can be considered as (1 × 2) cluster-crossover studies, but the order is always predetermined (no intervention, followed by the intervention)