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碳十四测年的误差有不同的性质。
一种是放射性测量所不可能避免的随机统计误差，也就是发表碳十四数据时一般同时标出该数据的一个标准差的统计误差，由于服从正态分布，如±40 的含义是如果不考虑";i:4;a:4:{s:3:"tag";s:1:"b";s:6:"option";N;s:8:"original";a:2:{i:0;s:3:"[B]";i:1;s:4:"[/B]";}s:8:"children";a:1:{i:0;s:12:"其他因素";}}i:5;s:1814:"，样品年龄应该有 68%的概率落在宽度为±40 的区间中（同时应该有 95%的概率落在±80 区间、有 99%的概率落在±120 区间）。这是提问者说的百科误差数据的情况，一般来说现在的实验室把标准差控制在正负三四十年是没问题的，早年发表的数据中这种误差会大一些。
问题是，这里的“其他因素”还有很多。有一类碳十四测年的误差，是由于碳十四测年所依赖的假设不完全成立导致的系统误差。比如年龄计算公式假设大气中碳十四同位素的丰度不变，但我们已经知道这只是近似成立，用现代（1950 年）的固定值计算就会出现系统误差，这种误差需要用其他独立的、高精度的定年手段（如树轮或珊瑚铀系年龄）做校正。没有树轮校正的碳十四年代大致会偏年轻，而且年龄越老偏离越大，对于一万年前的样品这种误差可以有一千年之多。所以只有校正过的碳十四年代才有意义。
树轮校正曲线并不是单调变化的，有很多百年或几十年幅度的起伏。曲线在某段的形状会对校正后的误差产生影响（这里所谓误差也是只考虑上述两者而不涉及别的因素），或者说校正后的误差大小取决于年代在树轮曲线上的位置。处于校正曲线上比较缓的位置，校正后误差就会变得比较大；处于校正曲线上比较陡的位置，校正后误差就比较小。提问者说的”出现了 200 年的误差“指的是这种情况，这和设备先进与否或工作人员水平等因素没有关系。如果你明知研究时间段处在校正曲线上的特定位置、会导致校正年代分辨率不足以满足研究需要，此时再做碳十四测年可能就是无用功。
";i:6;a:4:{s:3:"tag";s:3:"img";s:6:"option";N;s:8:"original";a:2:{i:0;s:5:"[IMG]";i:1;s:6:"[/IMG]";}s:8:"children";a:1:{i:0;s:83:"https://pic3.zhimg.com/v2-00306ade750d8cbd0d6f9f4a01645f9c_720w.jpg?source=8673f162";}}i:7;s:1137:"
正是由于这段曲线总体上坡度较缓，“所以处于这个区域中，应用单一样品测年，日历年校正误差一般都比较大。这样大的年代误差，无助于历史时期的年代讨论”（图文引自张雪莲 仇士华 蔡莲珍：《郑州商城和偃师商城的碳十四年代分析》，《中原文物》2005 年 1 期）。所以断代工程才引入系列样品的方法，因为系列样品校正后的测年精确度要远远高于单一样品的情况，标准差小到十几年、几年也是可能的。
————————
提问者说的 三万年年以内的遗物，年代测定误差范围会超出一万年左右吗？这又是另外的情况。
同一含碳样品中的不同炭质组分可能产生非常不同的年龄，样品总的混合年龄的考古意义可能是含糊的，而有些组分的碳十四年龄可能毫无考古意义，可以视为污染。如果把这个当作误差，那么对于旧石器时代样品，误差当然会超过一万年。
最近就有一个很好的例子，在李辉、孙雪峰等质疑福岩洞人化石年代的文章发表后（";i:8;a:4:{s:3:"tag";s:3:"url";s:6:"option";s:58:"https://www.zhihu.com/question/443750542/answer/1724650496";s:8:"original";a:2:{i:0;s:66:"[URL='https://www.zhihu.com/question/443750542/answer/1724650496']";i:1;s:6:"[/URL]";}s:8:"children";a:1:{i:0;s:104:"PNAS 新研究否定东亚人本地起源说，现代人抵达华南不足六万年，有哪些影响？";}}i:9;s:66:"），该文涉及碳十四年代部分受到了有力的反驳（";i:10;a:4:{s:3:"tag";s:3:"url";s:6:"option";s:81:"http://link.zhihu.com/?target=https%3A//mp.weixin.qq.com/s/F0VLir8dhd7RX9JdYRxH4Q";s:8:"original";a:2:{i:0;s:89:"[URL='http://link.zhihu.com/?target=https%3A//mp.weixin.qq.com/s/F0VLir8dhd7RX9JdYRxH4Q']";i:1;s:6:"[/URL]";}s:8:"children";a:1:{i:0;s:141:"学术争鸣 | “鹿牙”乌龙“人牙” ——对“古 DNA 和多种测年方式证实现代人晚到达中国南方”一文的评论";}}i:11;s:849:"）。
很多考古遗址的测年样品来自相对常见的动物骨骼（或牙齿），现在一般认为，只有提取出骨骼中的原生组分—胶原蛋白（或明胶蛋白）进行年代测定才能代表样品真实年龄，而 21 世纪初之前的样品前处理方法并不能排除胶原蛋白之外的其他成分，所发表的测年结果自然也不可靠（即使现在也未必能保证百分之百排除，只是确定比原先的做法能排除更多污染物）。
根据 Higham 的估计，由于现代碳的污染，对于 4 万年前这一时段来说，文献中多达 70％的年代数据可能太年轻，而且有时这种低估是非常严重的。详情可参考 Higham, T. European Middle and Upper Palaeolithic radiocarbon dates are often older than they look: problems with previous dates and some remedies. ";i:12;a:4:{s:3:"tag";s:1:"i";s:6:"option";N;s:8:"original";a:2:{i:0;s:3:"[I]";i:1;s:4:"[/I]";}s:8:"children";a:1:{i:0;s:9:"Antiquity";}}i:13;a:4:{s:3:"tag";s:1:"b";s:6:"option";N;s:8:"original";a:2:{i:0;s:3:"[B]";i:1;s:4:"[/B]";}s:8:"children";a:1:{i:0;s:2:"85";}}i:14;s:645:", 235–249 (2011).他认为老碳的污染相比于新碳来说微不足道：在一个距今 40000 年的样本中加入 10%的老碳，测得的年代是 40800 BP；而在样本中加入 10%的现代碳，测得的年代是 18000 BP，即使是 0.5%的现代污染也会给出完全扭曲的年龄(35 600 BP)。就国内来说，山顶洞遗址测年的前后变化也可以清晰地显示出前处理技术进步对于年代结果的影响，年代提前两万年对于认识人类历史来说是截然不同的图景。
值得相信的是，科学进步会逐渐减少一些判断的不确定性，一劳永逸的答案不值得相信。
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