[R] Re: diamond graphs

Frank E Harrell Jr fharrell at virginia.edu
Wed Aug 27 20:32:37 CEST 2003

On Wed, 27 Aug 2003 13:40:59 -0400
Alvaro Muñoz <amunoz at jhsph.edu> wrote:

> 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).

I appreciate your reply Dr Munoz.  I will have to disagree with you about the above although I think you made some good points.  I have seen many, many examples where categorization results in low-precision estimates and slight changes in the bins results in a significantly different landscape.  I have also seen many examples in epidemiology where stratified estimates have been misinterpreted.

Even though thermometer and similar plots have defects that you mentioned in your paper, they much more intuitively and precisely map values into the human brain.  The same is true of Cleveland's dot plots although one has to be careful, as you said in your article, about the ordering of stratifiers.

> 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.

Their belief that a patent on an idea may help achieve a wide use is sadly mistaken and is almost comical.  The statement "it would be available in widely used software which is not the case of the high end software" is very difficult to comprehend (especially in view of easy to use GUIs such as Rcmdr now available for R, as well as web interfaces).  There are several books I could recommend to your university staff.

> 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.

Unfortunately, I think that once the patent announcement was made, the number of individuals interested in the method lessened considerably.

> 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

Again I do thank you for your note.


Frank Harrell

Frank E Harrell Jr              Prof. of Biostatistics & Statistics
Div. of Biostatistics & Epidem. Dept. of Health Evaluation Sciences
U. Virginia School of Medicine  http://hesweb1.med.virginia.edu/biostat

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