Modelling heterogeneity of survival in band-recovery data using mixtures

Finite mixture methods are applied to bird band-recovery studies to allow for heterogeneity of survival. Birds are assumed to belong to one of finitely many groups, each of which has its own survival rate (or set of survival rates varying by time and/or age). The group to which a specific animal belongs is not known, so its survival probability is a random variable from a finite mixture. Heterogeneity is thus modelled as a latent effect. This gives a wide selection of likelihood-based models, which may be compared using likelihood ratio tests. These models are discussed with reference to real and simulated data, and compared with previous models.     

Unions and Employment Growth: Evidence from State Economic Recoveries

We test the hypothesis that in an economic recovery, unionization negatively affects job creation. We examine state-level job growth following two recent recessions, those with troughs in November 1982 and March 1991. In the five years following the troughs, we assess whether variations across states in union membership and right-to-work laws affect the rate of job growth. We find evidence that links union influence to slower job growth during an economic recovery, a finding consistent with previous studies reporting that unions negatively affect average employment and employment growth.

What If Hurricane Ivan Had Not Missed New Orleans?*

Author's Note: As I was developing the hypothetical situation depicting a devastating hurricane striking New Orleans, Louisiana, the disaster waiting to happen threatened to become a reality: Hurricane Ivan, a Category 4 hurricane (140 mph winds) fluctuating to a Category 5 (up to 155 mph winds), was slowly moving directly toward New Orleans. Forecasters were predicting a one‐in‐four chance that Ivan would remain on this direct path and would be an “extreme storm” at landfall. In reality, the storm veered to the north and made landfall east of Mobile Bay, Alabama, causing devastation and destruction well into the central Gulf shoreline and throughout the Southeast and the mid‐Atlantic states.