Introduction

The neverhpfilter package consists of 2 functions, 12 economic data sets, Robert Shiller’s U.S. Stock Market and CAPE Ratio data from 1871 through 2019, and a data.frame containing the original filter estimates found on table 2 of Hamilton (2017) <doi:10.3386/w23429>. All data objects are stored as .Rdata files in eXtensible Time Series (xts) format.

One of the first things to know about the neverhpfilter package is that it’s functions accept and output, xts objects.

An xts object is a list consisting of a vector index of some date/time class paired with a matrix object containing data of type numeric. data.table is also heavily used in finance and has efficient date/time indexing capabilities as well. It is useful when working with large data.frame like lists containing vectors of multiple data types of equal length. If using data.table or some other index based time series data object, merging the xts objects created by functions of this package should be fairly easy. Note xts is a dependency listed under the “Suggests” field of data.table DESCRIPTION file.

For more information on xts objects, go here and here.

yth_glm

The yth_glm function wraps glm and primarily exists to model the output for the yth_filter. On that note, the function API allows one to use the ... to pass any additional arguments to glm.

The yth_filter returns an object of class glm, so one can use all generic methods associated with glm objects. Here is an example of passing the results of a yth_glm model to the plot function, which outputs the standard plot diagnostics associated with the method.

library(neverhpfilter)

data(GDPC1)

log_RGDP <- 100*log(GDPC1)

gdp_model <- yth_glm(log_RGDP["1960/"], h = 8, p = 4)

plot(gdp_model)