This paper attempts to provide microfoundations for the knowledge production function in an idea-based growth model. Production of new ideas is made a function of newly reconfigured old ideas in the spirit of the way an agricultural research station develops improved plant varieties by cross-pollinating existing plant varieties. The model shows how knowledge can build upon itself in a combinatoric feedback process that may have significant implications for economic growth. The paper's main theme is that the ultimate limits to growth lie not so much in our ability to generate new ideas as in our ability to process an abundance of potentially new ideas into usable form.

From the viewpoint of a company's controlling shareholder, the optimal ownership structure generally involves some measure of dispersion, to avoid excessive monitoring by other shareholders. The optimal dispersion of share ownership can be achieved by going public, but this choice also entails some costs (the cost of listing and the loss of control over the shareholder register). If the controlling shareholder sells shares privately instead, he avoids the costs of going public but must tolerate large external shareholders who may monitor him too closely. Thus, the owner faces a trade-off between the cost of providing a liquid market and overmonitoring. The incentive to go public is stronger, the larger the amount of external funding required. The listing decision is also affected by the strictness of disclosure rules for public relative to private firms, and the legal limits on bribes aimed at dissuading monitoring by shareholders.

In 1839 the French government purchased the Daguerreotype patent and placed it in the public domain. Such patent buyouts could potentially eliminate the monopoly price distortions and incentives for rent-stealing duplicative research created by patents, while increasing incentives for original research. Governments could offer to purchase patents at their estimated private value, as determined in an auction, times a markup equal to the typical ratio of inventions' social and private value. Most patents purchased would be placed in the public domain, but to induce bidders to reveal their valuations, a few would be sold to the highest bidder.

We address long-standing problems in measuring medical inflation by estimating two types of price indices. The first, a Service Price Index, prices specific medical services, as does the current CPI. The second, a Cost of Living Index, measures a quality-adjusted cost of treating a health problem. We apply these indices to heart attack treatment between 1983 and 1994. More frequent reweighting and accounting for price discounts lowers the measured price change for heart attacks by three percentage points annually. Accounting for quality change lowers it further; we estimate that the real Cost of Living Index fell about 1 percent annually.

Using segment information from Compustat, we find that the investment by a segment of a diversified firm depends on the cash flow of the firm's other segments, but significantly less than it depends on its own cash flow. The investment by segments of highly diversified firms is less sensitive to their cash flow than the investment of comparable single-segment firms. The sensitivity of a segment's investment to the cash flow of other segments does not depend on whether its investment opportunities are better than those of the firm's other segments.

We use data on health plan choices by employees of Harvard University to compare the benefits of insurance competition with the costs of adverse selection. Moving to a voucher-type system induced significant adverse selection, with a welfare loss of 2 to 4 percent of baseline spending. But increased competition reduced Harvard’s premiums by 5 to 8 percent. The premium reductions came from insurer profits, so while Harvard was better off, the net effect for society was only the adverse selection loss. Adverse selection can be minimized by adjusting voucher amounts for individual risk. We discuss how such a system would work. Governments are increasingly turning to market forces as a way to limit the cost of social insurance. Traditionally, social insurance programs were operated as nonmarket goods; govern-ments mandated participation in a central program, collected revenues to finance the program, and ran the insurance system. There was no role for competition among suppliers in providing the basic benefit.

This paper comments on recent developments in the literature on the econometric analysis of international growth and convergence. It notes that panel estimates of the neoclassical model, accommodating level effects for individual countries through heterogeneous intercepts, deal with some of the econometric difficulties arising in some of the earlier cross-sectional studies. But it notes that, in dynamic panels, heterogeneity in growth effects and in speeds of convergence renders this estimator inconsistent also. The pervasiveness of such heterogeneity is demonstrated in three samples of countries, and the effects of (incorrectly) imposing homogeneity on estimated parameters are illustrated and discussed.