Assertion: placebo's study | /r/CapableOf | lack true control group
Facets:
Source sentences:
text: Although studies by Manchikanti et al.19,49 showed some benefit for lumbar medial branch blocks done with or without steroid, these studies lacked a true control group.
text: al.showed some benefit for lumbar medial branch blocks done with or without steroid, these studies lacked a true control group.