Explaining patterns of asset ownership in the economy is a central goal of both organizational economics and industrial organization. We develop a model of asset ownership in trucking, which we test by examining how the adoption of different classes of on-board computers (OBCs) between 1987 and 1997 influenced whether shippers use their own trucks for hauls or contract with for-hire carriers. We find that OBCs' incentive-improving features pushed hauls toward private carriage, but their resource-allocation-improving features pushed them toward for-hire carriage. We conclude that ownership patterns in trucking reflect the importance of both incomplete contracts (Grossman and Hart (1986)) and of job design and measurement issues (Holmstrom and Milgrom (1994)).

, and Stanford for comments. We also thank Michael Crum and several dispatchers and drivers for useful discussions. We gratefully acknowledge support from NSF grant SES-9975413 and the Harvard Business School Division of Research. The views expressed herein are those of the authors and not necessarily those of the National Bureau of Economic Research.

This paper examines the demand for on-board computers in trucking, distinguishing between their incentive-and resource-allocation-improving capabilities. I find that monitoring's incentive benefits are high when perquisite-taking is attractive to drivers, driver effort is important, and verifying drivers' actions to insurers is valuable. These results are consistent with agency theory and suggest that networking applications will raise the productivity and pay of difficult-toevaluate workers. I also find that monitoring's benefits are disproportionately resource-allocation-related when managerial decisions are least constrained. This suggests that networking applications' monitoring capabilities raise the returns to delegation when resource allocation decisions are routine and lower them when they are not.