Fraser River Sockeye Fisheries and Fisheries Management - Cohen ...

Appendix H Pre-season forecast: summary statistics and interpretations ofprecision, accuracy, and reliability for 19 indicator stocks in the Fraser River.ManagementGroup(IndicatorStock)MAPEError inReturnExplainedbyForecast(R 2 )RegressionSlope(Return :Forecast)RegressionInterceptMG Sizerelative tototal FraserReturnInterpretationRegression analysis: inferences about reliability, precision, andaccuracy relate to long-term trends (1980-2009).MAPE: expected error in any single year’s forecast.Early Stuart 53% 76%EarlySummerBowron 74% 8.7%Fennell 67% 16%0.99(significant)0.31(notsignificant)0.32(notnotsignificant3.3%significant 0.3%significant 0.5% Reliability: Relationship between forecast and return is statisticallysignificant, thus forecast is reliable. Precision: Moderate/Large amount of inter-annual variationexplained by forecasts (R 2 = 0.76) Accuracy: Slope is close to one and intercept is not significantlydifferent from zero, thus long-term accuracy is good. Expected Error: expect forecast to overestimate or underestimatereturn by 53% in any given year. Reliability: Relationship between forecast and return is notstatistically significant, thus returns vary at random relative toforecasts, making forecasts unreliable. Expected Error: expect forecast to overestimate or underestimatereturn by 74% in any given year. Reliability: Relationship between forecast and return is notstatistically significant, thus returns vary at random relative toH-1