Abstract: Method and apparatus for field evaluation of interrelated variables derived from event count per unit time. The method comprises simultaneously integrating selected multiple powers of the event count per unit time and registering only the resultant values. The apparatus is a self-contained portable electronic instrument which is employed in connection with an event count input device such as a digital anemometer which includes a plurality of digital rate multipliers and associated integrators coupled in a chain. It further includes power saving circuitry to turn off the apparatus when data retrieval conditions are not of interest. The method and apparatus are particularly useful for wind prospecting at remote sites where wind energy and optimum wind design speed are sought to be determined. The method and apparatus may also be employed for monitoring water flow, air and water pollution, traffic flow and any other phenomenon where an event count per unit time can be related to the phenomenon.