Identifying consumer segments based on COVID-19 pandemic perceptions and responses.

Consumer responses to the COVID-19 pandemic have varied widely. Thus, marketers need to understand consumer segments based on pandemic-related responses and behaviors. Through two studies conducted 9 months apart, we find that consumers shift from three segments in Study 1-the Apprehensive, the Prepared, and the Dismissive, to two segments in Study 2-the Dedicated and the Dismissive.

Monotonic single-index models to assess drug interactions.

Although single-index models have been extensively studied, the monotonicity of the link function f in the single-index model is rarely studied. In many situations, it is desirable that f is monotonic, which results in a monotonic single-index model that can be very useful in economics and biometrics. In this article, we propose a monotonic single-index model in which the link function is constructed using penalized I-splines along with constraints on coefficients to achieve monotonicity of the link function f.