This paper summarizes our efforts to compare calculations in several shallow water areas using range dependent models with results from coherent sound transmission experiments. The approach is to use detailed environmental and geophysical measurements to determine acceptable ranges of input parameters for the range dependent calculations, and then to determine within these bounds the ability to calculate the pressure amplitude, the phase of the signal, and the modal wave number spectrum. In addition, the coherence of the transmitted signal and the measurement of relative array signal gain were estimated. Although shallow water is known for its variability, these investigations clearly demonstrate predictable metrics of sound transmission, provided a sufficient type and an amount of environmental data are known. These investigations also show the key factors in this variability for acoustic predictability and highlight the areas of uncertainty. These results further suggest that shallow water variability and sound transmission can be calculated deterministically with dynamic changing environmental oceanographic variables.