Summary: The Defense Department's (DOD) centralized contracting data do not identify contracts that have been bundled. Bundling occurs when agencies package contract requirements into acquisitions, a practice that can effectively preclude small businesses from competing. The Small Business Administration (SBA) has begun to collect data on the extent of contract bundling where it has assigned resident representatives, but only about half of DOD's contract dollars are obligated at these locations. SBA's data-gathering effort could yield empirical data on the magnitude of the problem. Should such data be deemed insufficient, however, GAO believes that there should be reasonable assurances that any new collection effort will accomplish its objectives without the cost exceeding the expected benefits. DOD officials and others believe that bundling could harm small businesses that want to compete for government contracts but could also benefit government procurement activities by reducing their workload. GAO found no empirical evidence proving the costs or benefits of bundling. Existing guidance in the Federal Acquisition Regulation does not ensure that contracting officers properly identify all bundled contracts. Further, the existence of multiple definitions creates confusion about what constitutes bundling.