croston
Forecasts for intermittent demand using Croston's method
Returns forecasts and other information for Croston's forecasts applied to y.
 Keywords
 ts
Usage
croston(y, h=10, alpha=0.1, x=y)
Arguments
 y
 a numeric vector or time series
 h
 Number of periods for forecasting.
 alpha
 Value of alpha. Default value is 0.1.
 x
 Deprecated. Included for backwards compatibility.
Details
Based on Croston's (1972) method for intermittent demand
forecasting, also described in Shenstone and Hyndman (2005).
Croston's method involves using simple exponential smoothing (SES) on
the nonzero elements of the time series and a separate application
of SES to the times between nonzero elements of the time series. The
smoothing parameters of the two applications of SES are assumed to be
equal and are denoted by alpha
.
Note that prediction intervals are not computed as Croston's method has no underlying stochastic model. The separate forecasts for the nonzero demands, and for the times between nonzero demands do have prediction intervals based on ETS(A,N,N) models.
Value

An object of class
"forecast"
is a list containing at least the following elements:
is a list containing at least the following elements:The function summary
is used to obtain and print a summary of
the results, while the function plot
produces a plot of the
forecasts.The generic accessor functions fitted.values
and
residuals
extract useful features of the value returned by
croston
and associated functions.
References
Croston, J. (1972) "Forecasting and stock control for intermittent demands", Operational Research Quarterly, 23(3), 289303.
Shenstone, L., and Hyndman, R.J. (2005) "Stochastic models underlying Croston's method for intermittent demand forecasting". Journal of Forecasting, 24, 389402.
See Also
ses
.
Examples
fcast < croston(y)
plot(fcast)