In contrast, ESSA defines four levels of «evidence - based» practices: «strong,» with at least one well - designed and well - implemented experimental
study with a statistically significant, positive effect; «moderate,» with at least one well - designed and well - implemented quasi-experimental
study such as a matched - comparison group; «promising,» with at least one well - designed and well - implemented
correlational study with statistical controls for selection bias.
The
study presents both
correlational and experimental evidence confirming that cultural cognition shapes individuals» beliefs about the existence of scientific consensus, and the process by which they form
such beliefs, relating to climate change, the disposal of nuclear wastes, and the effect of permitting concealed possession of handguns.