[R] Re: diamond graphs

Alvaro Muñoz amunoz at jhsph.edu
Wed Aug 27 19:40:59 CEST 2003

Drs. Harrell and O'Keefe,

Thank you for your suggestions.

Regarding your comments about the content of the paper, I respectfully
disagree that "categorizing continuous variables is a fundamental violation
of statistical graphics," nor are you to assume that all categorizations are
arbitrary. In any case, the discussion section of our paper contains text
acknowledging that contour plots are a preferred option when the continuity
of variables is desired to be preserved. The hexagons we proposed seem, at
first glance, to be "unnecessarily complex" but they fulfill properties that
none of the other considered alternatives do (Table 1 and Figure 1 in paper
and Figure 6 using Trellis).

It is unfortunate that the comments from Dr. O'Keefe were based on a press
release and not on the manuscript itself. I apologize for the press release
implying no graphical progress in the 20th century. Many of his points are
addressed in the manuscript. Regarding the extension of the methods to
outcomes taking negative values (e.g., changes in markers), the use of two
colors is an alternative but the plotting of 0.5*[1+(outcome/max(|outcome|)]
and using the option E of Figure 1 in the paper will result in negative and
positive values having opposite topology (much as the contrast of
negative/positive bars in the unidimensional case). I will be happy to
expedite a reprint to Dr. O'Keefe. If you so desire, please email the
address to which it should be sent.

Although it is at odds with your beliefs, University staff working on
licensing and technology transfer believe that a patent may be a vehicle to
achieve a wide use. The audience of the proposed methods would be the end
users who are not sophisticated programmers and, therefore, the hope is that
it would be available in widely used software which is not the case of the
high end software (e.g., R). The proposed graph of 2D equiponderant display
of two predictors is just a display procedure, not an inferential tool. The
sophisticated analyst has little or no need for the proposed method. It does
overcome the pitfalls of 3D bar graphs and, therefore, has the potential of
improving the way we communicate our findings. Needless to say, were the
predictions of Dr. Harrell to be on target, we will change course as the
staff working on the licensing have planned from the start.

We will be happy to share the code we wrote to produce the figures in The
American Statistician paper with individuals wanting to use the software for
academic purposes. Please send request for it to afreeman at jhsph.edu.

In summary, our idea is a simple one (one that I refer as needing only 8th
grade geometry) and it is its simplicity which has been fun to peruse.

Alvaro Muñoz

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