Suppose that having established a marginal total effect of a point exposure on a time-to-event outcome, an investigator wishes to decompose this effect into its direct and indirect pathways, also known as natural direct and indirect effects, mediated by a variable known to occur after the exposure and prior to the outcome. This paper proposes a theory of estimation of natural direct and indirec...

Direct-to-Consumer Advertising (DTCA) of prescription drugs is controversial and has ambiguous potential welfare effects. In this paper, I estimate costs and benefits of DTCA in the market for antidepressant drugs. In particular, using individual health insurance claims and human resources data, I estimate the effects of DTCA on outcomes relevant to societal costs: new prescriptions, prices and...

This paper estimates the effect of marginal tax rates on demands for various financial assets, using the 1983-1989 Survey of Consumer Finances (SCF) panel. In the crosssection, marginal tax rates appear to have a strong and statistically significant influence on portfolio allocations, even after controlling for income and wealth. For example, people with high tax rates tend to hold larger share...

Suppose that having established a marginal total effect of a point exposure on a time-to-event outcome, an investigator wishes to decompose this effect into its direct and indirect pathways, also known as natural direct and indirect effects, mediated by a variable known to occur after the exposure and prior to the outcome. This paper proposes a theory of estimation of natural direct and indirec...

Regression discontinuity models, where the probability of treatment jumps discretely when a running variable crosses a threshold, are commonly used to nonparametrically identify and estimate a local average treatment effect. We show that the derivative of this treatment effect with respect to the running variable is nonparametrically identified and easily estimated. Then, given a local policy i...

Introduction: Since preserving the structure of treated teeth is a critical success factor, studying the effects of tooth structure loss on fracture resistance of the tooth tissue appears necessary. The aim of this study was to evaluate the consequences of the loss of different tissues regarding fracture resistance of teeth undergoing root canal treatment without the use of indirect restoration...

PURPOSE To evaluate the marginal fit of CAD/CAM copings milled from hybrid ceramic (Vita Enamic) blocks and lithium disilicate (IPS e.max CAD) blocks, and to evaluate the effect of crystallization firing on the marginal fit of lithium disilicate copings. MATERIALS AND METHODS A standardized metal die with a 1-mm-wide shoulder finish line was imaged using the CEREC AC Bluecam. The coping was d...

Objective: Cancer for Unknown Primary is cancer with unidentified metastases, and it is believed that CUP diagnosis affects survival in two different pathways; CUP may innately differ from other cancers with identified primaries, so the diagnosis itself can influence how long a person can survive. Another way is that CUP diagnosis affects how much people receive treatment, and the treatment, th...

PURPOSE The aim of this study was to evaluate the influence of the crown-to-implant (C/I) ratio on the change in marginal bone level around the implant and to determine the site-related factors influencing the relationship between the C/I ratio and periimplant marginal bone loss. METHODS A total of 259 implants from 175 patients were evaluated at a mean follow-up of five years. Implants were ...