We provide evidence that over the past 30 years, U.S. firms have expanded their scope of operations. Increases in scope and scale were achieved largely without increasing traditional operating segments. Scope expansion significantly increases valuation and is primarily realized through...

Patients needing kidney transplants may have willing donors who cannot donate to them because of blood or tissue incompatibility. Incompatible patient-donor pairs can exchange donor kidneys with other such pairs. The situation facing such pairs resembles models of the "double coincidence of...

In connection with an earlier paper on the exchange of live donor kidneys (Roth, Sonmez, and Unver 2004) the authors entered into discussions with New England transplant surgeons and their colleagues in the transplant community, aimed at implementing a Kidney Exchange program. In the course of...

Most transplanted kidneys are from cadavers, but there are also substantial numbers of transplants from live donors. Recently, there have started to be kidney exchanges involving two donor-patient pairs such that each donor cannot give a kidney to the intended recipient because of immunological...

For an incompatible patient-donor pair, kidney exchanges often forbid receipt-before-donation (the patient receives a kidney before the donor donates) and donation-before-receipt, causing a double-coincidence-of-wants problem. Our proposed algorithm, the Unpaired kidney exchange algorithm, uses...

We present an infinite horizon model with capital in which fiat money and barter are two competing means of payment. Fiat money has value because barter is limited by the extent of a double coincidence of wants. The pattern of exchange generally involves both money and barter. We find that the...

Firms invest heavily in customer capital, and such investment is a main source of intangible capital value. This study measures investment in customer capital using sales and marketing expense from income statements, information on salaries paid to workers in sales and marketing, and text from...

Observing the increasingly important roles played by the creation and transmission of information and tacit knowledge, we construct an information-network model incorporating both information transmitters and information aggregators. Given information-processing roles in aggregation or...