The author examines 22 experimental usability studies that appeared between 1980 and 1989. The discussion takes two directions: analysis of fundamental aspects of research coherence and unity by assessing the extent to which researchers jointly pursue a logical sequence of questions and the extent to which they integrate findings from prior studies into their own designs; and assessment of how trends in sample selection, size, and composition limit the strength of research conclusions. Ten years' worth of choices about samples show that a cumulative laxity in these choices has greatly constrained what one confidently can say experimental studies have proven about effective hard copy documentation. The author concludes by offering 13 recommended design strategies for future usability research.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>