The aim of this study was to measure the efficiency of the system by which scientists worldwide communicate results to each other, providing one measure of the degree to which the system, including all media, functions well. A randomly selected and representative sample of 246 active research scientists worldwide was surveyed. The main measure was the reported rate of “late finds”: scientific literature that would have been useful to scientists' projects if it had been found at the beginning of these projects. The main result was that 46% of the sample reported late finds (±6.25%, p0.05). Among respondents from European Union countries or other countries classified as “high income” by the World Bank, 42% reported late finds. Among respondents from low- and middle-income countries, 56% reported late finds. The 42% rate in high-income countries in 2009 can be compared with results of earlier surveys by Martyn (1964a, b, 1987). These earlier surveys found a rate of 22% late finds in 1963–1964 and a rate of 27% in 1985–1986. Respondents were also queried about search habits, but this study failed to support any explanations for this increase in the rate of late finds. This study also permits a crude estimate of the cost in time and money of the increase in late finds.