两者均与债或义务的履行相关。actual performance为“实际履行”，为债的履行原则之一，指债的双方当事人应当按债所规定的标的履行，不能由其他标的代替履行，也不可折合成金钱代偿。special performance (也称为specific relief)主要用于合同事项，指由法院签发命令，强制某人按其允诺履行某合同义务, 因其极具强制性，故为“强制履行”，须注意的是该术语经常被人混淆成actual performance而译为“实际履行”。
 
“ Special performance: A court-ordered remedy that requires precise fulfillment of a legal or contractual obligation when monetary damages are inappropriate or inadequate, as when the sale of real estate or a rare article is involved. ” Cf. Bryan A. Gamer, Black's Law Dictionary, 7th edition, at p. 1407, West Group (1999).