There have been 50 years of research in walking/working surface slipperiness and coefficient of friction (COF) measurements. Nevertheless, numerous standards address slip/fall accidents only in terms of requiring surfaces to be qualitatively "nonslippery." The literature useful for establishing quantitative criteria for "slippery" vs. "slip-resistant" have been summarized here. A performance definition for "slippery work surfaces" is proposed. Recommendations applicable to standards-making organizations are made, including changing terms such as "non-slip" to "slip-resistant" and defining "slippery" in terms of quantitative COF values. For persons walking unloaded on level surfaces, a COF standard of 0.5 would be reasonable. Research is recommended to determine if "slip-resistance" requirements and accident prevention could be achieved more easily be controlling the type of shoe, type of task, or amount of surface contaminant rather than controlling only the COF of the basic surface and its coating.