在 Stata 中生成年度观测值之间的百分比变化？

Question

如何使用gen或egen命令生成 Stata 中不同年份观测值之间的百分比变化？例如，我有 1990 年到 2010 年的观测值，每个观测值都有不同的支出值，并且我正在尝试生成一个新的观测值，其中包含 1990-1991 年、1991-1992 年等的百分比变化。

Answer 1

// 这是另一个衡量增长的示例：

clear
set obs 100
gen year = _n + 1959
gen expenditure = _n^(1/3) + runiform()
line expenditure year, yti("Synthetic data example")

//来自集权主义者：

bys year: g expendituregrowth=100*(expenditure[_n]-expenditure[_n-1])/expenditure[_n-1]

// 还：

gen expenditure_gr = (expenditure/expenditure[_n-1] - 1)*100 // growth rate for expenditure
gen expenditure_bl = 100*expenditure/expenditure[1] // baseline growth rate for expenditure; base 100 = 1960

line expenditure_gr year, yti("Growth rate")
line expenditure_bl year, yti("Growth rate (base 100 = 1960)")

expenditure_gr//我认为您正在寻找的计算。

// 如果你的数据结构良好，使用 Stata 与时间序列并轻松获得增长率：

tsset year, delta(1)
cap drop expenditure_gr
gen expenditure_gr = D.expenditure / 100*L.expenditure