Embodiments of the present invention are directed to increasing the reliability, precision, and resolution of identification, by analysis of comparative genomic hybridization (“CGH”) data and array-based comparative genomic hybridization (“aCGH”) data, of intervals along one or more chromosomes in which the copy number of the DNA subsequence within the interval in a sample genome is difference from the copy number of the DNA subsequence within a standard, or normal, genome. In various embodiments of the present invention, statistical data-quality measures are incorporated into comprehensive, quality-based interval-scores. In one described embodiment of the present invention, standard deviations for log ratios of signal intensities obtained by instrumental analysis of a microarray are used, along with the log ratios of signal intensities, to compute, for each interval, a weighted interval mean and interval variance, which are mathematically combined to produce a comprehensive, quality-based interval score that can be used to more reliably, precisely, and with greater resolution identify intervals along one or more chromosomes.