drsmooth (version 1.9.0)

lbcd: Linearity Below Cut-off Dose

Description

This function tests linearity below a specified dose.

Usage

lbcd(dosecolumn = "", targetcolumn = "", cutoffdose = 0, data = NA)

Arguments

dosecolumn

Name of dose column in input dataframe.

targetcolumn

Name of response column in input dataframe.

cutoffdose

Cut-off dose (numeric).

data

Input dataframe.

Value

A summary table showing the intercept and slope coefficients for the linear function below the user-specified dose, along with standard errors and significance tests.

Details

The user may provide a limit below which the linearity of the dose-response relationship is tested. A significant result indicates that the slope is non-zero below the user-specified cutoff dose.

The nlaad, nlbcd, and lbcd functions are currently only intended for use on continuous outcome data.

Examples

# Conducts a linear regression for all doses below 1.5
# (i.e., all dose levels up to and including 1.4929).
# The significance test on the dose coefficient is the test of non-zero linear slope:
lbcd("dose", "MF_Log", cutoffdose=1.5, data=DRdata)

# This produces an error, as no cutoffdose was specified:
## Not run: 
# lbcd("dose", "MF_Log", data=DRdata)
# ## End(Not run)