VALIDATING FOREST HARVESTING PRODUCTION EQUATIONS

The utility of production equations derived from time study data for forest harvesting operations is questionable when they are published without documented validation. Validation is frequently ignored, apparently because of the lack of standard procedures that are both theoretically sound and practically feasible. A methodology involving the use of independent observations of shift-level machine productivity is proposed and described in detail. Predicted productivity calculated using the production equations is tested statistically against actual productivity computed from shift-level data. The procedures are demonstrated in a case study of three phases of forest harvesting operations.