Despite the agreed-upon success of writing across the curriculum (WAC) programs among those who administer and teach them, there remains a paucity of hard evidence proving that they work. Most published articles touting the success of writing across the curriculum programs cite only anecdotal or soft evidence--not the kind of evidence that would win over a professor in economics or the sciences. A pilot program, supported by an internal grant from Southern Illinois University at Edwardsville's Excellence in Undergraduate Education Fund, attempted to evaluate the writing across the curriculum program there using procedures that would yield, at least in part, hard evidence. While the assessment yielded some soft evidence, such as summaries of student interviews, at least two components yielded evidence of the sort that would be respected university-wide. In one of these procedures, an economics professor taught a regular section of introductory economics at the same time that he taught a writing-intensive program. Test scores suggest strongly that the writing-intensive program benefited the students in it; test scores, while initially lower in the writing section, ended up higher than those in the other group. The second procedure yielded somewhat similar results. Judges experienced in reading essays in a number of disciplines examined 183 papers from both regular and writing intensive sections of many courses; results showed that more students from the writing intensive classes received "C or above." Contains seven references. (TB)