The range of existing techniques of ecological evaluation and their use in environmental planning in the United Kingdom is reviewed. it was concluded that there remains considerable scope for the use of ecological evaluations. There is a particular need for objective schemes which will generate data whichore useful at the level of producing detailed 'local' plans. Examination of three planning documents highlighted the confused manner in which 'the ecological argument' is presented at planning inquiries. It is suggested that ecological evaluations will help clarify the presentation of ecological data and shift the argument away from a preoccupation with rare species. Following a review of the three different approaches (schools) to ecological evaluation and an examination of the range of criteria measured a method is proposed of evaluating biological communities. Assessments of area, floral species richness, ground invertebrate diversity and rarity are used to calculate a community aggregate score. The maximum value for the C. A. S. is four and weighting is explicitly excluded from the formula. The order of results obtained for the C. A. S. were found to agree with a broader more subjective ecological evaluation of the study area. Sites enjoying statutory protection such as National Nature Reserves and Sites of-Special Scientific Interest generally obtained the highest scores. The average community aggregate scores for each community type agreed with the generally expected results, e. g. coniferous plantations consistently obtained low scores. Because of fundamental objections to the type of formulae often used in ecological evaluations and the elusive notion of ecological value an alternative approach is explored. It is suggested that techniques of multivariate analysis have a contribution to make to this study area. These multivariate techniques may have severe limitationsl when applied to this field of work, owing to their development from the calculation of correlation coefficients. Nevertheless, finallys alternative clustering techniques. are briefly discussed which may have a role to play in ecological evaluation. It should be recognised that there are some who would not wish to shift the emphasis away from rare species, and. see their preservation as the legitimate goal of ecological evaluation.