This paper presents the use of standardization or adjustment of rates and ratios in comparing two populations using single indices rather than a series of specific rates or ratios. Here the overall adjusted crude rate or the unadjusted crude rate for two populations will have same estimate irrespective of the nature of the standard population distribution. These results are obtained in all cases whenever the two standard distributions are of the total sample. In these cases the overall adjusted crude rates based on the two sets of directly adjusted rates would be equal to each other, although not necessarily always equal to the overall unadjusted crude rate as is found to be the case here. However, if the standard population distribution chosen for a given population is different from that chosen for another, then the two resulting estimated adjusted or standardized crude rates would most likely not be equal to each other.