任何现象随着时间的推移都在发生变化，要反映其发展变化的过程和规律，统计中所使用的基本方法是编制时间序列进行分析。编制时间序列，最重要的是遵循可比性原则，可比性原则强调时间序列中对应于不用时间的指标值可以相互比较，符合这一原则的时间序列才能够正确反映现象的 Any phenomenon changes over time, to reflect the process and laws of its development and changes, the basic method used in statistics is to compile time series for analysis. Compilation of time series, the most important thing is to follow the principle of comparability, comparability principle emphasizes the time series of indicators corresponding to the time can not be compared with each other, in line with this principle of the time series can correctly reflect the phenomenon