The following pages list a few basic statistics observed for the subjects involved in the study. Each subject is identified by the name of his group and a number. For example, “Novice–1” is the first subject of the Novice Programmer group. These names match the file names found in the publicly available trace data (Greenberg, 1988b).

The statistics include each user's number of login sessions, the command lines entered, the different commands used, the csh errors noted, the times history was used, and the different directories accessed. For example, Novice–1 entered 2,457 command lines over fifty-five login sessions. Of those lines, 213 produced csh errors. History was invoked thirty-seven times, eighteen different directories were visited, and sixty-seven different commands were used.