Evidence is insufficient because of: 1  The limited number or size of studies. 2  Important flaws in study design or methods. 3  Inconsistency of findings across individual studies. 4  Gaps in the chain of evidence. 5  Findings not generalizable to routine primary care practice. 6  Lack of information on important health outcomes.
Definition of jerk for English Language Learners. : 1  a stupid person or a person who is not well-liked or who treats other people badly. : 2  a quick pull or twist. : 3  a sudden sharp movement.
Definition of twitch. 1 : an act of twitching; especially : a short sudden pull or jerk. 2 : a physical or mental pang a twitch of remorse. 3 : a loop of rope or strap that is tightened over a horse's lip as a restraining device. 4a : a brief spasmodic contraction of the muscle fibersb : a slight jerk of a body part.