The central problem for the facility manager of large portfolios is not the accuracy of data, but rather data integrity. Data integrity means that it's (1) acceptable to the users; (2) based upon an objective source; (3) reproducible; and (4) internally consistent. Manns and Katsinas, in their January/February 2006 Facilities Manager article "Capital Budgeting Practices in Higher Education," pointed out two major failings in capital budgeting practices for higher education: states (large portfolio managers) lack comparative data, and formulae are not used by state higher education agencies (large portfolio managers) to request funds from their legislatures. One of the largest facilities portfolios in the U.S. is that of the U.S. Department of Defense with over 800,000 facilities. Nearly a decade ago, it faced problems similar to those highlighted by Manns and Katsinas: there was no comparative data between the individual military departments, and no formula was used to request funds from the U.S. Congress. This led the Congressional committees with oversight and funding responsibilities to question the "integrity" of the data. In this article, the author explores important issues critical to the evolution of data integrity.