lagging indicator       
noun [ C ]  finance & economics usually specialized uk/ˌlæɡ.ɪŋ ˈɪn.dɪ.keɪ.tər/ us/ˌlæɡ.ɪŋ ˈɪn.də.keɪ.t̬ɚ/
 滞后指标
something that shows what a situation has been like in previous weeks, months, etc., rather than showing what it is like now or will be like in the future
  The unemployment rate is a lagging indicator of the economy's overall performance. 失业率是经济总体表现的一个滞后指标。 
 Compare: leading indicator
 - More examples
 - Unemployment is a lagging indicator, he said, meaning that the circumstances that caused the August jump in joblessness actually occurred weeks or months earlier.
 - He said bankruptcy cases are a lagging indicator for the economy - which means if a recession began early this year, the caseload will begin to jump in the fall and early next year.
 - Some of the benchmarks are useful in predicting future trends, while others are lagging indicators.
 - Attitudes toward first ladies are "a lagging indicator about where women are in the country," says historian Lewis Gould.