Alice and Bob live in the forest. To sustain themselves, they collect fruits and berries and snare an occasional animal. The nights get cold, but Alice is a skillful fire-builder. Bob has never mastered this art. His fires fizzle and he never seems to collect the right kind of wood. Alice divides her time between collecting food and gathering wood. She does this in such a way that her marginal benefit from time spent collecting food is the same as that from gathering wood. Bob does not attempt to build fires. He spends all of his time gathering food, and every night slinks up and huddles beside Alice’s fire. Bob appreciates the fire’s warmth, but wishes it were larger. Bob has learned to leave morsels of food by the fire for Alice. Warmth and food are both “normal goods ” for Alice. The extra food that Bob leaves induces her to increase her total food consumption, but not by the total amount that Bob leaves for her. She uses some of the time saved by Bob’s gifts to gather more firewood. 1.1 Equilibrium with Unilateral Gifts–An Example Alice’s utility function is U(cA, y) = cAy where cA is the amount of food that she eats and y is the amount of wood on the fire. She has T hours to allocate between collecting food and wood. In an hour, she can collect either one unit of wood or πA units of food. If Bob leaves g units of food by the fire, she maximizes her utility by choosing y = 1

Does attendance affect performance in college economics courses? David Romer (1993) found that attendance did contribute significantly to the academic performance of students in a large intermediate macroeconomics course that he taught in the fall of 1990. (See the Summer 1994, Journal of Economic Perspectives [vol. 8, no. 3, pp. 205-15] for numerous comments on Romer.) This conclusion held even after controlling for student motivation which, it may be argued, is the true factor determining performance and is only approximated by attendance. An earlier study by Kang Park and Peter Kerr (1990) found that attendance was a determinant of student performance in a money and banking course, but not as important as a student's GPA and the percentile rank on a college entrance exam. A study by Robert Schmidt (1983) reported that time spent attending lectures contributed positively to performance in a macroeconomic Principles course. On the other side of the ledger is evidence from Neil Browne et al. (1991) showing that students who did not attend a typically structured class with lectures did just as well on the Test of Understanding College Economics (TUCE) as those students who attended a standard microeconomic Principles course. They also reported, however, that those students who attended the lectures performed better on essay questions than those who did not. A similar study by Campbell McConnell and C. Lamphear (1969) found no significant difference in the performance of students with no classroom attendance vis-a-vis those attending class. Finally, Stephen Buckles and M. E. McMahon (1971) found attendance at lectures that simply explained material covered in reading assignments did not enhance students' understanding of economics. In this paper we present new evidence on the effects of class attendance on student performance. Our results pertain to the Principles of Economics course as it is taught in a two-semester sequence at a medium-size, comprehensive state university.

�Inattentive agents update their information sporadically, and thus respond belatedly to news. We generate optimally inattentive behavior by assuming that to observe the value of his investment portfolio the consumer must pay a cost that is proportional to the portfolio’s contempo raneous value. It is optimal for the consumer to check his investment portfolio at equally spaced points in time, consuming from a riskless trans actions account in the interim. The riskless transactions account that finances consump tion guarantees that funds are never unwittingly exhausted. � We show that the optimal interval of time between consecutive observations of the value of the portfolio is the unique positive solution to a nonlinear equation. Quantitatively, even a small observation cost (one basis point of wealth) implies a substantial (eight-month) decision interval under conventional parameter values.

To identify the important tradeoffs in consulting a single expert for both diagnosis and treatment, we examine the costs and health outcomes of elderly Medicare beneficiaries with coronary artery disease. We compare the empirical consequences of diagnosis by cardiologists who can provide surgical treatment – “integrated” cardiologists – to the consequences of diagnosis by a nonintegrated cardiologist. Diagnosis by an integrated cardiologist leads, on net, to higher health spending but similar health outcomes. The net effect contains three components: reduced spending and improved outcomes from better allocation of patients to surgical treatment options; increased spending conditional on treatment option; and worse outcomes from poorer provision of nonsurgical care.

Many individuals' choices and valuations involve a degree of uncertainty/imprecision. This paper reports an experiment designed to obtain some measure of imprecision and to examine the extent to which it can explain preference reversals of two opposite forms, one of which appears not to have been reported previously. The model of imprecision we examine not only predicts both patterns but also provides an account of earlier results that are otherwise not well explained. The results suggest that any successful descriptive theory of choice and valuation will need to allow in some way for the imprecision surrounding people's decisions.

Inexperienced women, along with economics and business majors, are much more susceptible to the winner’s curse, as are subjects with lower SAT/ACT scores. There are strong selection effects in bid function estimates for inexperienced and experienced subjects due to bankruptcies and bidders who have lower earnings returning less frequently as experienced subjects. These selection effects are not identified using standard econometric techniques but are identified through experimental treatment effects. Ignoring these selection effects leads to misleading estimates of learning.