seqintegration: Integrative potential

Description

Returns Brzinsky-Fay's index of integrative potential for each sequence, either a table with the index for each state or a vector with the index for the selected state.

Usage

seqintegration(seqdata, state=NULL, pow=1, with.missing=FALSE)

Arguments

seqdata

a state sequence object (stslist) as returned by seqdef.

state

character string. The state for which to compute the integration index (see Details). When NULL the index is computed for each state.

pow

real. Exponent applied to the position in the sequence. Higher value increase the importance of recency (see Details). Default is 1.

with.missing

logical: should non-void missing values be treated as a regular state? If FALSE (default) missing values are ignored.

Value

when state=NULL, a numeric matrix with a row for each sequence and a column by state and a single column when a state is provided.

Details

The index of integrative potential measures the capacity to integrate the selected state within the sequence, i.e. the tendency in to reach the selected state and end up in it. The index is defined as the sum of the position numbers occupied by the selected state in the sequence over the sum of all position numbers. Formally, for a sequence $s$ of length $L$, and numbering the positions $i$ from 1 to $L$, the index is

$$integration = \sum_{(i | s_i = state)} i^{pow} / \sum_i i^{pow}$$

where $state$ is the selected state.

The exponent $pow$ permits to control the focus given on the latest positions in the sequence. The higher pow, the higher the importance of the last positions relative to the first ones.

When with.missing = FALSE, the index is adjusted by subtracting the sum of the positions numbers of the missings from the denominator. To compute the index for the missing state, with.missing should be set as TRUE.

References

Brzinsky-Fay, C. Unused Resources: Sequence and Trajectory Indicators. International Symposium on Sequence Analysis and Related Methods, Monte Verita, TI, Switzerland, October 10-12, 2018

Examples

Run this code

# NOT RUN {
data(ex1)
sx <- seqdef(ex1[,1:13], right="DEL")

seqintegration(sx)
seqintegration(sx, with.missing=TRUE)
seqintegration(sx, state="B")
seqintegration(sx, state="B", pow=1.5)

# }

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