Linear Approximations to the Census and BLS Seasonal Adjustment Methods
人口普查局与 BLS 季节调整方法的线性近似
The Census and BLS ratio-to-moving-average seasonal adjustment methods are usually specified by procedural steps. They can be written mathematically as combinations of linear and non-linear operations on the logarithms of the original series. For some purposes the non-linear operations can be ignored. The Census and BLS historical seasonal factors are almost identical to those from a simpler model using ratios to a centered 12-term moving average. They also closely resemble…