Factor model is an appealing and effective analytic tool for high-dimensional time series, with a wide range of applications in economics, finance and statistics. One of the fundamental issues in using factor model for time series in practice is the determination of the number of factors to use....

Using a large-scale panel data set, we trace the evolution of incomes and well-being around the entry into 'solo self-employment' - that is, running a business without employees. We find that solo self-employment is used to self-insure against employment shocks: employment rates fall and poverty...