如何使用gen或egen命令来生成不同年份在Stata观测值之间的百分比变化？ 例如，我对1990年观测到2010年，每对支出不同的值，我想生成一个与1990 - 1991年，1991 - 1992年等变化率的新观察
Answer 1:
//这是与增长的另一项措施的例子：
clear
set obs 100
gen year = _n + 1959
gen expenditure = _n^(1/3) + runiform()
line expenditure year, yti("Synthetic data example")
// 从Statalist ：
bys year: g expendituregrowth=100*(expenditure[_n]-expenditure[_n-1])/expenditure[_n-1]
//另外：
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)")
//的计算expenditure_gr是什么，我认为你正在寻找。
//如果都能很好地形成你的数据，使用Stata的时间序列，轻松地获得了增长速度：
tsset year, delta(1)
cap drop expenditure_gr
gen expenditure_gr = D.expenditure / 100*L.expenditure
文章来源: Generate percent change between annual observations in Stata?
