We develop a model for decomposing the covariance structure of panel data on firms into a part due to permanent heterogeneity, a part due to differential histories with unknown ages, and a part due to the evolution of economic shocks to the firm. Our model allows for the endogenous death of...

Our two related goals in this paper are the following: Firstly and mainly, we want to examine the effects of major changes in modelling strategy and econometric methodology, over the past twenty years, on estimation of firm-level investment equations using panel data. Secondly, we try to assess...