Rising college enrollment over the last quarter century has not been met with a proportional increase in college completion. Comparing the high school classes of 1972 and 1992, we show declines in college completion rates have been most pronounced for men who first enroll in less selective public universities and community colleges. We decompose the decline into the components due to changes in preparedness of entering students and due to changes in collegiate characteristics, including type of institution and resources per student. While both factors play some role, the supply-side characteristics are most important in explaining changes in college completion. (JEL I23)

Total student loan debt rose to over $800 billion in June 2010, overtaking total credit card debt outstanding for the first time. By the time this article sees print, the continually updated Student Loan Debt Clock will show an accumulated total of roughly $1 trillion. Borrowing to finance educational expenditures has been increasing—more than quadrupling in real dollars since the early 1990s. The sheer magnitude of these figures has led to increased public commentary on the level of student borrowing. We move the discussion of student loans away from anecdote by establishing a framework for considering the use of student loans in the optimal financing of collegiate investments. From a financial perspective, enrolling in college is equivalent to signing up for a lottery with large expected gains—indeed, the figures presented here suggest that college is, on average, a better investment today than it was a generation ago—but it is also a lottery with significant probabilities of both larger positive, and smaller or even negative, returns. We look to available—albeit limited—evidence to assess which types of students are likely to be borrowing too much or too little.

We would like to thank participants at the NBER Seminar on the Economics of Higher Education for helpful comments. We are grateful to Tom Kane, Bill Johnson and John Pepper for reading an early draft of the paper and offering most helpful comments. The views expressed herein are those of the authors and not necessarily those of the National Bureau of Economic Research.

Cannabis sativa has been used for recreational, therapeutic and other uses for thousands of years. The plant contains more than 120 C terpenophenolic constituents named phytocannabinoids. The Δ-tetrahydrocannabinol type class of phytocannabinoids comprises the largest proportion of the phytocannabinoid content. Δ-tetrahydrocannabinol was first discovered in 1971. This led to the discovery of the endocannabinoid system in mammals, including the cannabinoid receptors CB and CB. Δ-Tetrahydrocannabinol exerts its well-known psychotropic effects through the CB receptor but this effect of Δ-tetrahydrocannabinol has limited the use of cannabis medicinally, despite the therapeutic benefits of this phytocannabinoid. This has driven research into other targets outside the endocannabinoid system and has also driven research into the other non-psychotropic phytocannabinoids present in cannabis. This chapter presents an overview of the molecular pharmacology of the seven most thoroughly investigated phytocannabinoids, namely Δ-tetrahydrocannabinol, Δ-tetrahydrocannabivarin, cannabinol, cannabidiol, cannabidivarin, cannabigerol, and cannabichromene. The targets of these phytocannabinoids are defined both within the endocannabinoid system and beyond. The pharmacological effect of each individual phytocannabinoid is important in the overall therapeutic and recreational effect of cannabis and slight structural differences can elicit diverse and competing physiological effects. The proportion of each phytocannabinoid can be influenced by various factors such as growing conditions and extraction methods. It is therefore important to investigate the pharmacology of these seven phytocannabinoids further, and characterise the large number of other phytocannabinoids in order to better understand their contributions to the therapeutic and recreational effects claimed for the whole cannabis plant and its extracts.