Optimal designs of both public policy and fundraising mechanisms rely on the extent to which charitable donations are motivated by altruism and "warm-glow." Motives for giving influence donor responses to changes in public funding for projects, and influence the effectiveness of a wide range of solicitation strategies, such as the characteristics of the ask, whether past donations should be announced to future donors, and whether a charitable lottery is likely to increase the funds raised.To identify preferences for charitable giving, researchers center on measuring how much individual donations respond to, or are crowded out by, donations by others. We explore this central crowd-out test and demonstrate that it is not well suited for identifying preferences.The theory of pure altruism assumes that the sole motive for charitable giving is the utility derived from the charity's output, e.g., from children in need getting aid * Ottoni-Wilhelm: Department of Economics, Indiana University-Purdue University Indianapolis, 425 University Boulevard, CA516, Indianapolis, IN 46202 (email: mowilhelm@iupui.edu); Vesterlund: Department of Economics, University of Pittsburgh, 4928 WW Posvar Hall, Pittsburgh, PA 15260, and NBER (email: vester@ pitt.edu); Xie: Department of Economics, Concordia University, 1455 Maisonneuve Boulevard W, Montreal, QC H3G 1M8, Canada (email: huan.xie@concordia.ca). This paper was accepted to the AER under the guidance of Marianne Bertrand, Coeditor. We thank Kong Wah Lai, Michael Menietti, and Linnea Warren, who helped conduct the experiments. We thank Sandi Wraith and the American Red Cross of South Western Pennsylvania for their help in facilitating our research. We are grateful to Bo Honoré for extending his Stata code for the twosided fixed-effects censored estimator to models with variable censoring levels. We thank