This article identifies the major factors that are influencing the rate of market penetration of office automation equipment, presents trend data on national and industry investment in office automation and other equipment, extrapolates these trends to 1995, and compares several recent penetration forecasts against the trend data. The data show that office-intensive industries such as finance are rapidly increasing their capital/labor ratios, and that office automation equipment represents a significant portion of this total investment (about 40%). The relative importance of equipment costs in determining the penetration rate is likely to decline as training and implementation costs increase and become more visible, and as more managerial and professional tasks become automated. Investment trends offer a useful basis from which to analyze and assess market penetration forecasts. The plausibility of forecasts can be judged by comparing them against extrapolations of past investment behavior, particularly the ratio of investment in equipment of all kinds to industry product or GNP. A forecast that appears plausible on these grounds must be examined further to determine whether it accounts for the effects of other costs that are more difficult to measure, and for less quantifiable factors that, overall, could play a dominant role in shaping market penetration patterns and rates.