...index variables, stochastic process, ageing 2 Frailty is a non-specific state of increasing ris[gap=292]关键词：脆弱，索引变量，随机过程，老化2弱者是一种非特异性的风险增加，这反映了多系统的状态 ..
Messrs Frey and Stutzer find that a one-point increase in this democracy index, after stripping out the effects of the other variables, increases the share of people who say they are very happy by 2.7 percentage points.
They use a forecasting model that relies, in particular, on the close historical relationship between company profits and two variables, total corporate investment in equipment and the commodity-price index published by The Economist.