The focus of this Element is on the idea that choice is hierarchical so that there exists an order of acquisition of durable goods and assets as real incomes increase. Two main approaches to deriving such an order are presented, the so-called Paroush approach and Item Response Theory. An...

We distinguish between three types of outliers in a one-way random effects model. These are formally described in terms of their position relative to the main part of the observations. We propose simple rules for identifying such outliers and give an example which involves median-based statistics.