# growth.rate: Growth Rates of Time Series In tis: Time Indexes and Time Indexed Series

## Description

Get or set growth rates of a `tis` time series in annual percent terms.

## Usage

 ```1 2``` ```growth.rate(x, lag = 1, simple = T) growth.rate(x, start = end(x) + 1, simple = T) <- value ```

## Arguments

 `x` a `tis` time series or something that can be turned into one by `as.tis` `lag` number of lags to use in calculating the growth rate as outlined in the details below `simple` simple growth rates if `TRUE`, compound growth rates if `FALSE` `start` the first `ti` time index for which values of `x` should be replaced to make `growth.rate(x[start]) == value`. `value` desired growth rates

## Details

An example: Suppose `x` is a quarterly series, then if `simple` is `TRUE`,

`growth.rate(x, lag = 3)` == `100 * ((x[t]/x[t-3]) - 1) * (4/3)`

while if `simple` is `FALSE`

`growth.rate(x, lag = 3)` == `100 * ((x[t]/x[t-3])^(4/3) - 1)`.

## Value

`growth.rate(x)` returns a `tis` series of growth rates in annual percentage terms.

Beginning with the observation indexed by `start`,

`growth.rate(x) <- value`

sets the values of `x` such that the growth rates in annual percentage terms will be equal to `value`. `x` is extended if necessary. The modified `x` is invisibly returned.

tis documentation built on Sept. 29, 2021, 1:06 a.m.