fert {eha}

Marital fertility nineteenth century

Description

Birth intervals for married women with at least one birth, 19th northern Sweden

Usage

data(fert)

Format

A data frame with 12169 observations the lengths (in years) of birth intervals for 1859 married women with at least one birth. The first interval (parity = 0) is the interval from marriage to first birth.

id

Personal identification number for mother.

parity

Time order of birth interval for the present mother. The interval with parity = 0 is the first, from marriage to first birth.

age

The age of mother at start of interval.

year

The calendar year at start of interval.

next.ivl

The length of the coming time interval.

event

An indicator for whether the next.ivl ends in a new birth (event = 1) or is right censored (event = 0). Censoring occurs when the woman ends her fertility period within her first marriage (marriage dissolution or reaching the age of 48).

prev.ivl

The length of the previous time interval. May be used as explanatory variable in a Cox regression of birth intervals.

ses

Socio-economic status, a factor with levels lower, upper, farmer, and unknown.

parish

The Skelleftea region consists of three parishes, Jorn, Norsjo, and Skelleftea.

Details

The data set contain clusters of dependent observations defined by mother's id.

Source

Data is coming from The Demographic Data Base, Umea University, Umea, Sweden.

References

https://www.umu.se/enheten-for-demografi-och-aldrandeforskning/

Examples

data(fert)
fit <- coxreg(Surv(next.ivl, event) ~ ses + prev.ivl, data = fert, subset =
(parity == 1))
summary(fit)