Festing M F
MRC Toxicology Unit, Carshalton, Surrey, UK.
Lab Anim. 1992 Oct;26(4):256-68. doi: 10.1258/002367792780745788.
The factors which need to be taken into account in designing a 'good' experiment are reviewed. Such an experiment should be unbiased, have high precision, a wide range of applicability, it should be simple, and there should be a means of quantifying uncertainty (Cox 1958). The relative precision due to the use of randomized block designs was found to range from 96% to 543% in 5 experiments involving 30 variables. However, a survey of 78 papers published in two toxicology journals showed that such designs were hardly used. Similarly, designs in which more than one factor was varied simultaneously ('factorial designs') were only used in 9% of studies, though interactions between variables such as dose and strain of animal may be common, so that single factor experiments could be misleading. The consequences of increased within-group variability due to infection and genetic segregation were quantified using data published by Gärtner (1990). Both substantially reduced precision, but toxicologists continue to use non-isogenic laboratory animals, leading to experiments with a lower level of precision than is necessary. It is concluded that there is scope for improving the design of animal experiments, which could lead to a reduction in animal use. People using animals should be required to take formal training courses which include sessions on experimental design in order to minimize animal use and to increase experimental efficiency.
本文回顾了设计“良好”实验时需要考虑的因素。这样的实验应该是无偏的，具有高精度、广泛的适用性，应该简单，并且应该有一种量化不确定性的方法（考克斯，1958年）。在涉及30个变量的5个实验中，发现使用随机区组设计的相对精度在96%至543%之间。然而，对在两份毒理学杂志上发表的78篇论文的调查显示，这种设计几乎没有被使用。同样，同时改变多个因素的设计（“析因设计”）仅在9%的研究中被使用，尽管动物的剂量和品系等变量之间的相互作用可能很常见，因此单因素实验可能会产生误导。利用加特纳（1990年）发表的数据，对感染和基因分离导致的组内变异性增加的后果进行了量化。这两者都大大降低了精度，但毒理学家仍继续使用非近交系实验动物，导致实验精度低于必要水平。结论是，改进动物实验设计仍有空间，这可能会减少动物的使用。使用动物的人员应该被要求参加正式的培训课程，其中包括实验设计课程，以便尽量减少动物的使用并提高实验效率。
