1. The following is an abstract from the paper "Discrimination in Health Care: A Field Experiment on the Impact of Patients' Socioeconomic Status on Access to Care," by Silvia Angerer, Christian Waibel, and Harald Stummer.

We employ a large-scale field experiment to investigate the impact of patients' socioeconomic status on access to care. We request an appointment at more than 1,200 physicians in Austria, varying the educational level of the patient. Our results show that overall patients with a university degree receive an appointment significantly more often than patients without a degree. Differentiating between practice assistants and physicians as responders, we find that physicians provide significantly shorter response times and marginally significant shorter waiting times for appointments for patients with than without a university degree. Our results thus provide unambiguous evidence that discrimination by health providers contributes to the gradient in access to care. Furthermore, we argue that our results are consistent with implicit bias for practice assistants and statistical discrimination based on financial incentives for physicians.

The endogenous variable of interest to the researchers is _____, and the outcome variable is _______. The authors attempt to address this endogeneity by using a____.

a) socio-economic status defined by level of education; access to care (defined by appointment availability and wait times); a natural experiment.

b) access to care (defined by appointment availability and wait times); socio-economic status defined by level of education; a randomized experiment

c) socio-economic status defined by level of education; access to care (defined by appointment availability and wait times); a randomized experiment.

d) access to care (defined by appointment availability and wait times); socio-economic status defined by level of education; a natural experiment