Data Comparability: An Objective for Precipitation Chemistry Monitoring

Data comparability is a stated or implied goal of a number of networks today (for example, the Utility Acid Precipitation Study Program [UAPSP]). This concept is indeed very important if a research objective such as the “national objective” on precipitation chemistry monitoring is to be met using the combination of all the existing precipitation chemistry monitoring networks in North America. An analysis of the definition of data comparability shows that two steps are involved in establishing data comparability of two data sets: (1) to judge the adequacy of the data sets toward accomplishing the objective and (2) to determine the uncertainty of each data set and that of the combined data set.

Two methods are described to improve data comparability. The two methods can be represented by (1) the responsibilities of the data gatherer and (2) the responsibilities of the data analyst. In applying these methods towards meeting an example objective, it is shown that implementing and reporting quality control/quality assurance on the part of the data gatherers (that is, network operators) is the key stumbling block in the data analyst's attempts to determine the degree of data comparability. The UAPSP network is described, and the efforts to improve data comparability are discussed. The UAPSP has implemented both internal quality control and independent quality assurance to meet its responsibilities as a data gatherer. The UAPSP also sponsored a workshop in Aug. 1982 to promote discussion of ways to improve data comparability among the networks in the future.