measurement.rate: measurement.rate

In tvtools: Comprehensive Tools for Panel Data Analysis - 'tvtools'

measurement.rate

Description

Calculates the proportion of unique subjects remaining under observation and those no longer observed at a specified time point during the follow-up period within a panel data structure. This metric is crucial for evaluating the coverage and retention of subjects in longitudinal studies.

Usage

measurement.rate(
  dat,
  id.name = "id",
  t1.name = "t1",
  t2.name = "t2",
  time.point = 0,
  grouping.variables = NULL
)

Arguments

dat	A data frame structured as panel data.
id.name	The character name of the identifying variable within dat, used to track subjects across multiple rows.
t1.name	The character name of the time variable within dat representing the start (left endpoint) of observation intervals.
t2.name	The character name of the time variable within dat representing the end (right endpoint) of observation intervals.
time.point	A numeric value specifying the point in time at which the measurement rate should be calculated. Subjects observed at this point are considered active.
grouping.variables	A character vector of variable names from dat used to group the results. Proportions are calculated within these groups.

Value

Returns a data table that includes the specified grouping variables, the number of subjects observed at the given time.point, the total number of unique subjects, and two calculated rates: 'rate.observed' and 'rate.not.observed'. 'rate.observed' is the proportion of subjects active at the specified time point, and 'rate.not.observed' is the proportion no longer observed. This output is instrumental for analyzing subject retention and attrition over the course of the study.

tvtools documentation built on Oct. 8, 2024, 5:09 p.m.