under-dispersionn.

1935 Ann. Bot. 49 794 There is significant underdispersion or aggregation among the individuals of the population.

1946 Ecology 27 329/2 The writer [sc. L. C. Cole] prefers the terms ‘contagious’ and ‘negatively contagious’ to ‘overdispersion’ and ‘underdispersion’ both of which have suffered reversals of meaning in the hands of different authors.

1962 D. R. Cox Renewal Theory iii. 42 Expression..is less than one, so that there is apparent under-dispersion relative to the Poisson distribution.

1964 K. A. Kershaw Quantitative & Dynamic Ecol. vi. 98 Several species showed either ‘overdispersion’ or ‘underdispersion’.

1940 Proc. Linn. Soc. New S. Wales LXV. 135 The distribution of individual species in the areas examined must be either random, or over- or under-dispersed.

1957 P. Greig-Smith Quantitative Plant Ecol. iii. 56 The former has been termed overdispersed (referring to the distribution curve obtained) and the latter underdispersed. Unfortunately these terms have sometimes been used in the reverse sense (referring to the pattern of individuals on the ground)..and are better avoided.

1982 G. A. F. Seber Estimation of Animal Abundance (ed. 2) xii. 479 The classification into overdispersed and underdispersed is not sufficiently fine.