The increasing availability of recycled organic matter (ROM) composts prepared from a wide range of ingredients such leaf and yard debris, food scraps and manures, is challenging from both a laboratory analyst and a grower perspective. Lab test methods to accommodate compost testing have been largely adapted from soil procedures and environmental and wastewater methods, yet not all methods lead to similar conclusions of usefulness to growers. Among the chief concerns of representation of analytical findings are salinity, nutrient availability, activity of carbon, and stability and maturity based on respirometry or heat indexes. Since composts are frequently used at massive application rates due to their relative stability and good appearance, accurate and appropriate constituent reporting become very important to warrant success and safety to the grower. Laboratory survey work reported to date with composted products indicates widely varying test results in all categories of analysis, and where plant trials are involved, indices of performance vary enormously. A Swiss survey suggests that professional compost sales grew in the 1990's, then declined, as markets could not adjust to widely varying qualities of the materials. A combination of government mandates and incentives to recycle organic matter and industry risks in assuming the responsibility have resulted in a deadlock of quality standards development in Europe and America. The emergence of new bacterial pathogens with implications for soil amendment strategies exacerbates the need for careful identify protocols and analyses of ROM composts. This paper presents tabular data for agronomic and environmental qualities of a variety of compost products and examines the potential significance based not current understanding of soil mixes and in relation to growth chamber bioassays. We introduce the use of a mathematical matrix which aids interpretation of complex analytical data to determine what composts may be best suited for.