Fatal Error: An error that affects a party's substantive rights or the outcome,and thus is grounds for reversal if the party properly objected.

Fatal Error也称为Reversible Error（“可撤销判决的错误”），Harmful Error（“有害错误”）。Fatal Error为侵犯当事人实质性权利或影响案件结果的“严重错误”,此种错误可使得当事人有权以此为由要求法院重新审理。

Harmless Error: An error that does not affect a party's substantive rights or the case's outcome. It is not grounds for reversal.

Harmless Error为“无害错误”，也可表达为Technical Error, Error In Vacuo。指审判中出现的未损害当事人实质性权利或未影响案件结果的轻微错误，上诉法院一般不得以此为由推翻原判而命令重新审理。

参考双语例句：

It is necessary for China to establish the rule of harmless error in the criminal procedure law.

我国应当借鉴美国的经验，在刑事诉讼法中明确确立无害错误规则。

The Dispute Tribunal has awarded compensation in the following cases: (a) for the lost chance of being considered for a position or for the lost chance of being appointed to a position, based on the speculation that the staff member had a “high” chance of being appointed, a 50 per cent chance of being appointed or even a 10 per cent chance of being appointed; (b) for a procedural error even when the staff member did not suffer any injury as a result of such error; and (c) for violating obligations of courtesy, even though the Dispute Tribunal found that the contested administrative decision was lawful. 、争议法庭在下述案件中裁定了赔偿金：(a)原因是失去了被考虑担任某一职位的机会或者失去了被任命担任某一职位的机会，依据是该工作人员有“很大”的任用机会，有50%的任用机会，或者甚至是10%的任用机会的推测；(b)原因是程序性错误，即使工作人员并没有因这种错误而遭受损害；以及(c)原因是违反了礼节性做法的义务，即使争议法庭认定有争议的行政决定是合法的。