The objective of this work was to formulate a simple model that can be used for assessing the statistical significance of the grain-boundary character distribution in a material. Increased interest in the control of the grain-boundary character distribution to influence grain boundary properties has led to numerous studies on the characterization of grain-boundary type without regard to the statistical significance of the results. Specifically, the model was developed to determine, a priori, the number of boundaries that need to be characterized such that the fraction of boundaries of a particular type is known to within a specific fractional error. The inclusion of experimental error in the model accounts for the misidentification of boundary type in the characterization process. The model also addresses the statistical significance of boundary degradation by boundary type. This is a more restrictive application of the same formalism in that a low probability of degradation (e.g. cracking, corrosion and cavitation) on a scarce boundary type may result in very few measurements of degraded boundaries and, hence, poor statistics. The objective of the model is again to determine, a priori, the number of boundaries that need to be characterized for the result to have statistical significance. The model is applied to two sets of data obtained on nickel-based alloys to show, firstly that, for a coincident site lattice boundary fraction larger than 0.2 to be known with a fractional error less than 0.10, a minimum of 500 boundaries need to be characterized and, secondly, the number of grain boundaries that need to be characterized to provide statistical significance in the comparison between the Brandon criterion and the Palumbo et al. criterion for correlation with grain-boundary cracking.