以上词组均为侵权法中的术语。concurrent negligence为“并存过失”，指两个或两个以上侵权行为人（被告）独立（不一定同时）对一个受害人（原告）加害，造成同一伤害或损失而负有过失责任[1]。joint negligence为“共同过失”，其与concurrent negligence很相似，差别在于其是指两个或两个以上的侵权行为人同时而非独立加害而导致一个伤害之过失责任[2]。comparative negligence为“比较过失”或“相对过失”，主要用在赔偿金的确认上，即按行为人（被告）的过失大小决定其承担的赔偿金的比例，而受害人（原告）也会因其自身的过失而减少索赔所得[3]。contributory negligence多为“混合过失”或“与有过失”（现有不少英汉词典将其当作“共同过失”，此纯属ー种错误[4]），指伤害或损失是因加害人和受害人，即原告和被告共同责任所致[5]。目前美国很多州的有关contributory negligence的法则已经被comparative negligence的法则所替代。
[1] "The negligence of two or more parties acting independently but causing the same
damage." Cf. Bryan A. Gamer, Black's Law Dictionary, 7th edition, at p. 1056, West Group (1999).
[2] "The negligence of two or more persons acting together to cause an accident." Id. at p. 1057.
[3] "The modem doctrine that as between a plaintiff and a defendant in a tort case, and sometimes as among several defendants, fault ( and liability for damages) should be allocated in proportion to each party's contribution to the injury or loss complained." Cf. James E. Clapp, Random House Webster's Dictionary of the Law, at p. 297, Random House, New York (2000).