The Recreation Opportunity Spectrum (ROS) system is used by the USDA Forest Service and USDI Bureau of Land Management for inventorying, classifying, and managing wildlands for recreation. Different ROS classes from the Colorado and Arkansas Rivers in Colorado were compared, using visitor survey data collected in 1979 and 1981, to see if the different classes offered different r e creational experience opportunities. No difference between classes was found. Six possible reasons for not finding a difference. are discussed. The usefulness of ROS at the broader levels of planning and the needs at more detailed levels of planning are noted. (KEY TERMS: river recreation; recreation experience; Recreation Opportunity Spectrum (ROS) system; forest recreation.) 'Paper No.