Little research attention has been paid to the systematic validation of mathematical indices of social structure. The validation strategies in use remain largely implicit and generally fail to appreciate the multi-dimensionality of structure. The current paper proposes a new method designed to avoid these shortcomings and reports the results of its use in evaluating a set of 11 indices Potentially useful in measuring communication structure. Recommendations regarding the use of these indices for particular research purposes are made, along with suggestions for future research. (Author/AA)