The decennial census is a constitutionally mandated undertaking that is used, among other things, to apportion seats in Congress, redraw congressional districts, help annually allocate billions of dollars in federal aid to state and local governments, and inform investment decisions by the public and private sectors. As shown in figure 1, the cost of enumerating each housing unit has escalated from around $16 in 1970 to around $97 in 2010, in constant 2010 dollars (an increase of over 500 percent). Costs are driven in part by, the mail response rate—a key indicator of a cost-effective census—which has declined from 78 percent in 1970 to 63 percent in 2010. A variety of factors account for the declining response rate, including increases in non-English speakers and people residing in makeshift and other nontraditional living arrangements. Given these and other sociodemographic challenges, the Bureau has been investing substantially more resources each decade just to try and match the results of prior enumerations. According to the Bureau, several factors were behind the escalating costs of the 2010 Census, such as the need to hire about 585,000 temporary field staff to count the more than 46- million households that did not mail back their census forms, and substantial investments in updating the Bureau’s address list—including address canvassing, a door-to-door effort to verify the address list’s accuracy in 2009. USPS also faces financial challenges, especially as customers shift to electronic communications and electronic payments. Total mail volume peaked in fiscal year 2006 at 213-billion mail pieces and is expected to decline by about 22 percent by the end of fiscal year 2011, to about 167-billion mail pieces. In the first three quarters of this fiscal year, the volume for First-Class Mail—USPS’s most profitable product—declined by 6.5 percent compared to the same period last year. Over the last 5 fiscal years, USPS has experienced a cumulative net loss of nearly $23 billion, and has already reported a net loss of nearly $5.7 billion through the first nine months of fiscal year 2011. Further, USPS anticipates ending this fiscal year with a loss of approximately $10 billion. USPS plays a key role in the success of the decennial census. Since the advent of the mail-out/mail-back census in 1970, USPS has helped to develop and improve the Bureau’s census address list and has delivered and returned census forms. A complete and accurate address list is the cornerstone of a successful census because it both identifies all households that receive a census questionnaire and serves as the control mechanism for following up with individuals at households that fail to respond. USPS maintains and regularly updates a database (its Delivery Sequence File) of all addresses to which it delivers mail and provides this information biannually to the Bureau. The collaborative efforts between the Bureau and USPS have generally gone well and demonstrate the importance of key leading collaboration practices that we previously identified. Some of these include:  establishing compatible policies, procedures, and other means to operate across agency boundaries;  defining and articulating a common outcome; and  identifying and addressing needs by leveraging resources. For example, in 1990, the Bureau and USPS established the interagency Joint Committee for Census Planning to develop opportunities for cooperation in support of the decennial census. This committee defines and agrees on the respective roles and responsibilities of the two agencies and addresses the compatibility of standards and policies. In 1995, USPS and the Bureau signed a memorandum of understanding that is still in effect which defined how the two agencies will share addresses in order to conduct the decennial census. Moreover, for the 2010 Census the agencies agreed to have USPS destroy rather than return certain undeliverable mail pieces, resulting in cost savings of $250,000 for the Bureau and over $12 million in savings for USPS, according to Bureau estimates. Officials from both the Bureau and USPS believe their collaboration related to the 2010 Census was mutually beneficial. For example, Bureau officials stated that USPS delivered 417-million census mail pieces, virtually 100 percent of which were delivered on time, and according to USPS’s 2010 Comprehensive Statement on Postal Operations, census mailings generated over $202 million in revenue. Additionally, the 2010 Census provided USPS with an opportunity to demonstrate the benefits of a relatively new mail product, the Intelligent Mail Barcode, which enables mailers to track the progress of their mail through the many stages of processing to delivery. The Bureau was the largest-ever user of Intelligent Mail Barcode for a single-mailing effort, and the success of the mailing could help USPS market the barcode to other customers. Among other benefits, the barcode enabled the Bureau to identify which census forms were in the mail-stream on their way back to the Bureau 3 to 5 days sooner than if the Bureau had not used this technology (see fig. 2). As a result, the Bureau was able to remove 11-million addresses from the replacement mailing, which led to nearly $5 million in postage savings. The Bureau and USPS are engaging in efforts to enhance their collaboration. For example, given the Bureau’s use of the Intelligent Mail Barcode for the 2010 Census, the Bureau considered using the barcode for its American Community Survey. Although Bureau officials indicated they planned to use the Intelligent Mail Barcode for the American Community Survey, since the completion of our audit, the Bureau determined that the cost savings were insufficient to justify the required investment to use the technology. The Bureau is in the planning stages of working with USPS and other federal agencies on a new program called the Geographic Support System Initiative, which is intended to allow government agencies at all levels to regularly share and continuously update their address lists, making them more detailed and accurate. Specifically, the Bureau plans to partner with USPS and other federal agencies as well as approximately 40,000 tribal, state, and local governments. According to current plans, USPS will continue providing the Bureau with addresses from its Delivery Sequence File. Likewise, tribal, state, and local governments, which maintain address lists for purposes such as emergency response and property assessment, will have the opportunity to share addresses with the Bureau throughout the decade, rather than solely 2 years prior to the decennial, as had been the case in prior decennials. However, Bureau officials have noted that in moving forward one challenge will be coordinating adherence to the confidentiality protections included in the Bureau’s Title 13 provisions and USPS’s Title 39. Ultimately, by leveraging address information from USPS and other government entities during the non-decennial years, Bureau officials anticipate that they will be in a position in 2019 to move away from a full door- to-door address canvassing of every housing unit, to a more targeted effort. Address canvassing is one of the Bureau’s largest and most expensive field operations, and Bureau officials stated a more targeted program could lead to significant cost savings. The Bureau and USPS also plan to update their 1995 memorandum of understanding to, among other matters, reflect routine changes that have occurred over time (e.g., update contact information), and help ensure that both agencies benefit from their collaborative efforts. Bureau officials explained that under the 1995 memorandum, the agencies’ collaboration typically benefited the Bureau more than USPS. Now both agencies would like to improve each other’s address and geographic information. One new effort anticipated under the revised memorandum of understanding would provide USPS with the Bureau’s geographic data products and support, which USPS hopes to use to improve its mail routing and other business decisions. The revised memorandum of understanding is expected to be approved later this year. Opportunities exist for the Bureau to take advantage of the knowledge and experience of USPS mail carriers, including retirees. Bureau and USPS officials agree that USPS city and rural mail carriers are familiar with the local living conditions in their communities and that this knowledge could help the Bureau conduct aspects of the 2020 Census more effectively. Mail carriers have experience and knowledge about the dwellings on their routes and could help find unconventional and hidden housing units (e.g., converted basements and attics) and identify single versus multi-unit homes. Residents of these households are often more difficult to find and count. Additionally, in some communities, mail carriers have information about hazardous locations along delivery routes (e.g., houses with an unchained dog or other dangers such as structurally unsafe porches), which could make census workers’ jobs safer and easier. In hiring for the 2010 Census, the Bureau did not do a targeted recruitment of USPS employees and retirees, a potential missed opportunity given that there were approximately 300,000 USPS mail carriers and approximately 100,000 additional retired mail carriers at that time. Still, the Bureau hired approximately 2,400 USPS employees as temporary census employees at the Bureau’s $15 average pay rate. The potential benefits of mail carriers’ local knowledge was evident, for example, in a case we observed in Louisiana, where a retired mail carrier used his knowledge of local living conditions to successfully manage census field operations in the area most devastated by Hurricane Katrina. Specifically, the mail carrier knew which addresses to remove and which to add to the address list based on his experience delivering mail in those neighborhoods. In moving forward for 2020, a targeted campaign—e.g., via job listings in mail carrier union newsletters and publications—could help the Bureau recruit more mail carriers to conduct census operations. That said, using full-time mail carriers paid at much higher USPS wage rates—either for additional duties during the work day or as part of a “postal holiday” (where regular mail operations would be suspended in order to conduct census activities)—would not be cost-effective.