R: Volatility of individual state sequences

seqivolatility {TraMineR} | R Documentation

## Volatility of individual state sequences

### Description

Returns Brzinsky-Fay's objective volatility of each sequence.

### Usage

      seqivolatility(seqdata, w=.5, with.missing=FALSE, adjust=TRUE)

### Arguments

`seqdata` | a state sequence object (`stslist`) as returned by `seqdef`.
`adjust` | Logical. Should the indicator be adjusted such that it can reach its bounds 0 and 1. Deafult is `TRUE` (see Details).
`w` | Real in the range [0, 1]. Default is 0.5. Weight given to the proportion of states visited (see Details).
`with.missing` | Logical: should non-void missing values be treated as a regular state? If `FALSE` (default) missing values are ignored.

### Details

The (objective) volatility is the weighted average between the proportion pvisited of states visited and the frequency ftrans of transitions (state changes). Formally,

volatility = w * pvisited + (1-w) * ftrans

The proportion of states visited is computed as (visited - 1)/(|a| - 1) when `adjsut=TRUE` and as visited / |a| when `adjsut=FALSE`. Here, visited is the number of states visited and |a| the size of the alphabet.

The frequency of transition is ftrans = \frac{transn}{max.transn} where transn is the number of transitions (state changes) within the sequence, and max.transn the maximum possible transitions in the sequence.

For the normative volatility, see `seqipos`. For alternative measures of sequence complexity see `seqST`, `seqici`, `seqindic`.

### Value

A numeric vector with the volatility of each sequence.

### Author(s)

Gilbert Ritschard

### References

Brzinsky-Fay, C. Unused Resources: Sequence and Trajectory Indicators. International Symposium on Sequence Analysis and Related Methods, Monte Verita, TI, Switzerland, Oct 10-11, 2018

Ritschard, G. (2021), "Measuring the nature of individual sequences", Sociological Methods and Research, doi: 10.1177/00491241211036156.

### See Also

`seqintegr`, `seqipos`, `seqindic`

### Examples

    data(ex1)
    sx <- seqdef(ex1[,1:13], right="DEL")

    seqivolatility(sx)
    seqivolatility(sx, adjust=FALSE)
    seqivolatility(sx, with.missing=TRUE)
    seqivolatility(sx, w=.7, with.missing=TRUE)

[Package TraMineR version 2.2-3 Index]