g_glf_inv

vector of scores on the latent scale $(-\infty,\infty)$

vector of 3 elements: <code>M</code>, the offset of the curve, <code>B</code>, the slope of the curve, and <code>T</code>, the symmetry
of the curve

Inverse of a parametric version of the g function
following Richards (1959):
$$g^{-1}(W) = \left( \frac{e^{B(W-M)}}{T+e^{B(W-M)}}  \right)^{\frac{1}{T}}$$

logistic

Richards

A regression framework for response variables which are continuous self-rating scales such as the Visual Analog Scale (VAS) used in pain assessment, or the Linear Analog Self-Assessment (LASA) scales in quality of life studies. These scales  measure subjects' perception of an intangible quantity, and cannot be handled as ratio variables because of their inherent nonlinearity. We treat them as ordinal variables, measured on a continuous scale. A function (the g function, currently the generalized logistic function) connects the scale with an underlying continuous latent  variable.  The link function is the inverse of the CDF of the assumed underlying distribution of the latent variable. Currently the logit link, which corresponds to a standard logistic distribution, is implemented.

g_glf_inv: Inverse of generalized logistic g function

Description

Usage

Arguments

Value

References

See Also