Bookmark and Share

Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: logit transformation of RHS variable

From (Brendan Halpin)
Subject   Re: st: logit transformation of RHS variable
Date   Thu, 05 Jan 2012 01:25:00 +0000

On Wed, Jan 04 2012, Raymond Lim wrote:

> Hello Statalisters,
> I have an independent variable that I believe that needs to be
> transformed because it's bounded between 0 and 1, and it's easier to
> go from 0 to .10 than say .80 to .90. My question is, can I use a
> logit transformation on this RHS variable (new_x = x / (1 - x)? Or are
> logits usually for LHS variables only?

I'd read the logit transformation as suggesting it is harder rather than
easier to go from 0 to 0.1 than from 0.8 to 0.9. In log-odds 0 is
-infinity and 0.1 is log(0.1111) or about -2.2, whereas 0.8 to 0.9 is
1.4 to 2.2. The logit makes it hard to move at both extremes, but easy
around 0.5.

It may be that the "fractional logit model" may be what you need:

glm y x1 x2 ... , family(binomial) link(logit) robust

Googling "fractional logit" gets as the first hit. Maarten
may have more to say himself, but I would imagine he is currently


Brendan Halpin,   Department of Sociology,   University of Limerick,   Ireland
Tel: w +353-61-213147  f +353-61-202569  h +353-61-338562;  Room F1-009 x 3147    ULSociology on Facebook:         twitter:@ULSociology
*   For searches and help try:

© Copyright 1996–2018 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   Site index