About: http://webisa.webdatacommons.org/230336913

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	There is no true control group, but epidemiologists say these studies are good for showing whether something has a good or bad effect on health, though not for quantifying it.
http://www.w3.org/ns/prov#wasQuotedFrom	greatergreaterwashington.org