seasonal is an easy-to-use and full-featured R interface to X-13ARIMA-SEATS, the seasonal adjustment software developed by the United States Census Bureau. The latest CRAN version of seasonal fixes several bugs and makes it easier to access output from multiple objects. See here for a complete list of changes.

seas() is the core function of the seasonal package. By default, seas() calls the automatic procedures of X-13ARIMA-SEATS to perform a seasonal adjustment that works well in most circumstances:

library(seasonal)
seas(AirPassengers)

For a more detailed introduction, read our article in the Journal of Statistical Software.

Multiple series adjustment

The previous version has introduced the adjustment of multiple series in a single call to seas(). This has removed the need for loops or lapply() in such cases and finally brought the composite spec to seasonal.

As Brian Monsell pointed out, this was not enough to access the output from the composite spec. The latest CRAN version fixes this problem.

Multiple adjustments can be performed by supplying multiple time series as an "mts" object:

library(seasonal)
m0 <- seas(cbind(fdeaths, mdeaths), x11 = "")
final(m0)

This performs two seasonal adjustments, one for fdeaths and one for mdeaths. The vignette on multiple adjustments describes how to specify options for individual series.

Accessing composite output

The composite argument is a list with an X-13 specification applied to the aggregated series:

m1 <- seas(
  cbind(mdeaths, fdeaths),
  composite = list(),
  series.comptype = "add"
)

With version 1.9 can now use out() to access the output of the composite spec:

out(m1)

We can also use series(), e.g., to access the final, indirectly adjusted series via the composite spec (see ?series for all available series):

series(m1, "composite.indseasadj")