Contents
What is a synthetic counterfactual?
Synthetic control methodology (SCM) allows the construction of a counterfactual by selecting a weighted average of the outcome variable from a group of units similar to the treated unit. Abadie and Gardeazabal1 first set out SCM in a study looking at the impact of terrorism on the economy of the Basque region of Spain.
What is a control arm clinical trial?
Those who are in the control arm will not receive the new medication, device or treatment that is under study, to provide a comparison to see how the innovation compares against no treatment or an old treatment. …
Which is the best model for synthetic control?
Abadie, Diamond, and Haimueller motivate the synthetic control method using the following model: where is the outcome for unit at time , are common time effects, are observed covariates with time-varying parameters , are unobserved common factors with as unobserved factor loadings, and is an error term.
How is synthetic control used in health research?
This month’s method is synthetic control. Health researchers are often interested in estimating the effect of a policy of change at the aggregate level. This might include a change in admissions policies at a particular hospital, or a new public health policy applied to a state or city.
How does the synthetic control method work with longitudinal data?
With longitudinal data we could just throw all this into a regression model and estimate the parameters. However, generally, this doesn’t allow for unobserved confounders to vary over time. The synthetic control method does. Abadie, Diamond, and Haimueller motivate the synthetic control method using the following model:
Is there a novel method for unobserved confounding?
Controlling unobserved confounding still remains a great challenge in observational studies, and a series of strict assumptions of the existing methods usually may be violated in practice. Therefore, it is urgent to put forward a novel method.