The integrity of research and expert opinions in Washington came into question last week, prompting the resignation of Robert Litan, an economist, from his position as a nonresident fellow at the Brookings Institution. Senator Elizabeth Warren raised the issue of a conflict of interest in Mr. Litan's testimony before a Senate committee. The testimony was based on a paper Mr. Litan had prepared for the Capital Group, a mutual fund company. Mr. Litan disclosed that the Capital Group, which has a stake in the debate, had funded his paper, but he did not disclose that it had also commissioned it. At stake is the integrity of the research process and the trust the nation puts in experts, who advise governments and testify in Congress. Had [Litan's] conclusions not pleased the Capital Group, it would probably have found a more compliant expert. And the reputation of not being "cooperative" would have haunted Mr. Litan's career as a consultant. The practice of bending an opinion for money is so widespread as to be the norm. By shedding light on how funding of research can affect its content, Senator Warren increased the reputational penalty for experts who bend to special interests. But we need two more changes. Congressional testimony and policy papers should be posted online at least two weeks in advance of a hearing and open for comments. And all expert witnesses should be disclosed to the public, with a time delay if needed for confidentiality.