infonet-economy

Mixed methods systematically combine multiple research approaches—either in basic parallel, sequential, or conversion designs or in more complex multilevel or integrated designs. Multilevel mixed designs are among the most valuable and dynamic. Yet current multilevel designs, which are rare in the mixed methods literature, do not strongly integrate qualitative and quantitative…

This report examines the measurement invariance of the Personal Well-being Index with 8 items (PWI-8). University students (N = 5731) from 26 countries completed the measure either through paper and pencil or electronic mode. We examined uni-dimensional structure of PWI and performed a Multi-group CFA to assess the measurement invariance across the 26 countries, using conventional…

Measurement invariance is a necessary precondition for meaningful cross-country comparisons, and three levels have been differentiated: configural, metric, and scalar. Unfortunately, establishing the most stringent form, i.e., scalar measurement invariance, across groups is difficult. Recently, Muthén and Asparouhov proposed testing for approximate rather than exact measurement…

Markowitz (1952) portfolio selection requires an estimator of the covariance matrix of returns. To address this problem, we promote a nonlinear shrinkage estimator that is more flexible than previous linear shrinkage estimators and has just the right number of free parameters (i.e., the Goldilocks principle). This number is the same as the number of assets. Our nonlinear shrinkage…

From 2004 to 2012, the German social health insurance levied a co-payment for the first doctor visit in a calendar quarter. We develop a new model for estimating the effect of such a co-payment on the individual number of visits per quarter. The model combines a one-time increase in the otherwise constant hazard rate determining the timing of doctor visits with a difference-in-…

Excess zeros are encountered in many empirical count data applications. We provide a new explanation of extra zeros, related to the underlying stochastic process that generates events. The process has two rates, a lower rate until the first event, and a higher one thereafter. We derive the corresponding distribution of the number of events during a fixed period and extend it to…