Abstract Instrumental variables allow for quantification of cause and effect relationships even in the absence interventions. To achieve this, a number causal assumptions must be met, most important which is independence assumption, states that instrument any confounding factor independent. However, if this condition not can we still work with imperfect instrumental variables? Imperfect instrum...

Instrumental variable analyses are increasingly used in epidemiologic studies. For dichotomous exposures and outcomes, the typical 2-stage least squares approach produces risk difference estimates rather than relative risk estimates and is criticized for assuming normally distributed errors. Using 2 example drug safety studies evaluated in 3 cohorts from Pennsylvania (1994-2003) and British Col...

This paper determines the properties of standard generalized method of moments (GMM) estimators, tests, and confidence sets (CSs) in moment condition models in which some parameters are unidentified or weakly identified in part of the parameter space. The asymptotic distributions of GMM estimators are established under a full range of drifting sequences of true parameters and distributions. The...

This study examines the relationship between teleworking, gender roles and happiness of couples using data from the British Household Panel Survey (BHPS) and the Understanding Society Survey (USS) during the period 1991-2012. Various approaches are followed, including Probit-adapted fixed effects, multinomial Logit and Instrumental variables (IV). The results support that both men and women who...

During the last two decades there has been an increase in using dynamic tariffs for billing household electricity consumption. This has questioned the suitability of traditional pricing schemes, such as two-part tariffs, since they contribute to create marked peak and offpeak demands. The aim of this paper is to assess if two-part tariffs are an efficient pricing scheme using Spanish household ...

This paper explores the link between utilization of ambulatory care and the likelihood of rehospitalization for an avoidable reason in veterans served by the Veteran Health Administration (VA). The analysis used administrative data containing healthcare utilization and patient characteristics stored at the national VA data warehouse, the Corporate Franchise Data Center. The study sample consist...

Data for discrete ordered random variables are often characterised by “excessive” zero observations. Traditional ordered probit models have limited capacity in explaining the preponderance of zero observations, especially when the zeros may relate to two distinct situations of non-participation and infrequent participation (or consumption), for example. We propose a zero-inflated ordered probit...