Le Quatrième Coin/The 4th-Corner

Pierre Legendre
May 1996
Département de sciences biologiques
Université de Montréal
The 4th-corner method, which was presented at the NT-95 meeting, offers a way of analyzing relationships between the supplementary variables associated with the rows and columns of a binary (presence-absence) data table (Legendre et al., 1997). The problem which motivated the development of the method is the following: How does one relate the biological and behavioral characteristics of animals (matrix B) to habitat characteristics of the locations at which they are found (matrix C), given the distribution of animals across sampling sites (matrix A)? Statistical parameters in matrix D are estimated by the following matrix operation: D = C A' B. They are tested for significance using a permutation procedure. Random permutations of matrix A can be obtained under four different permutational models. Documents available for distribution include:

Software downloads

The program documentation files have been designed to be printed in either US Letter or A4 formats. Reference:
Legendre, P., R. Galzin & M. L. Harmelin-Vivien. 1997. Relating behavior to habitat: solutions to the fourth-corner problem. Ecology 78: 547-562.