The original design, and what it actually measuredThe first study, run by psychologist James Pennebaker and his student Sandra Beall, only had access to a fairly blunt outcome measure: health center visits. Subjects wrote about either “personally traumatic life events” or trivial topics on four consecutive days, fifteen minutes a session, and researchers then pulled their health center records for the following six months. As Pennebaker later described the finding, students who had written about trauma “ended up going to the student health center over the next 6 months at about half the rate of students in the control condition.” The trauma group in that first study was actually three groups — subjects wrote about the facts of their trauma, their feelings about it, or both — and the health-center drop was concentrated in the group that wrote about both. The second measure moved in the same direction but wasn’t strong enough on its own to count as a reliable finding.