associative model | Forecasting technique that uses explanatory variables to predict future demand.
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bias | Persistent tendency for forecasts to be greater or less than the actual values of a time series.
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centered moving average | A moving average positioned at the center of the data that were used to compute it.
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control chart | A visual tool for monitoring forecast errors.
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correlation | A measure of the strength and direction of relationship between two variables.
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cycle | Wavelike variations lasting more than one year.
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Delphi method | An iterative process in which managers and staff complete a series of questionnaires, each developed from the previous one, to achieve a consensus forecast.
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error | Difference between the actual value and the value that was predicted for a given period.
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exponential smoothing | A weighted averaging method based on previous forecast plus a percentage of the forecast error.
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forecast | A statement about the future value of a variable of interest.
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irregular variation | Caused by unusual circumstances, not reflective of typical behavior.
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judgmental forecasts | Forecasts that use subjective inputs such as opinions from consumer surveys, sales staff, managers, executives, and experts.
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least squares line | Minimizes the sum of the squared vertical deviations around the line.
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linear trend equation | Ft = a + bt, used to develop forecasts when trend is present.
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mean absolute deviation (MAD) | The average absolute forecast error.
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mean absolute percent error (MAPE) | The average absolute percent error.
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mean squared error (MSE) | The average of squared forecast errors.
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moving average | Technique that averages a number of recent actual values, updated as new values become available.
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naive forecast | A forecast for any period that equals the previous period's actual value.
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predictor variables | Variables that can be used to predict values of the variable of interest.
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random variations | Residual variations after all other behaviors are accounted for.
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regression | Technique for fitting a line to a set of points.
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seasonal relative | Percentage of average or trend.
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seasonal variations | Regularly repeating movements in series values that can be tied to recurring events.
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seasonality | Short-term regular variations related to the calendar or time of day.
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standard error of estimate | A measure of the scatter of points around a regression line.
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time series | A time-ordered sequence of observations taken at regular intervals.
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time-series forecasts | Forecasts that project patterns identified in recent time-series observations.
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tracking signal | The ratio of cumulative forecast error to the corresponding value of MAD, used to monitor a forecast.
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trend | A long-term upward or downward movement in data.
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trend-adjusted exponential smoothing | Variation of exponential smoothing used when a time series exhibits a linear trend.
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weighted average | More recent values in a series are given more weight in computing a forecast.
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