Well, sure, but applicants aren't profs. Thinking about it, Amy's practice does seem reasonable to me. In light of that, I'll weaken the statement I made before... I'm thinking that so long as the first authors on those papers are your ref writers, it should be okay. But, I'd say that you should still be waiting until you have the data collected and things good to go for analysis, or even preliminary analysis done, before adding it to the CV as a work-in-progress. psychplease is right that you could bring in a manuscript written in the time between apps and interviews, but if you have a line about a project you're still formulating, ethics could get delayed or the project might just not work, and you could have nothing to show for that line on your CV. Not too impressive...