summary.trend {poptrend}

Summary of trend estimates

Description

Computes a trend or index estimate for each time point in the survey.

Usage

## S3 method for class 'trend'
summary(object, ciBase = NULL, alpha = 0.05, ...)

Arguments

object

A trend object returned by ptrend.

ciBase

A time point or function used to compute the baseline of the trend. If the argument is numeric, the point in the trendGrid argument of the function ptrend closest to this value will be taken as the baseline (i.e. the estimated trend will be 1 at this point). If the argument is a function, the function is applied to trends and the resulting value is used as the baseline. By default, the first time point is taken as the reference.

alpha

alpha level for approximate confidence intervals.

...

Not used.

Details

For a smooth or loglinear trend model the function computes an estimate of the trend value for each time point in the survey. By default, the reference value is the first time point. Note that if the trend model was fitted with random effects, the random effects are not included in the estimate. Thus the estimate refers to the long-term component.

For an index trend model the index at each time point is computed.

If bootstrap samples are available, bootstrap confidence intervals for the trend or index values are also computed.

Author(s)

Jonas Knape