Discussion: View Thread

  • 1.  validated instrument for rating "quality" or "effectiveness" of graphical display of data

    Posted 9 days ago

    (Cross-posted to Consultants and Graphics forums)

    I attended a medical conference recently, along with about 350 medical students, residents, and faculty. I gave a presentation on effective graphical display of data, with my take on the principles of Tufte, Cleveland, and Cairo (although clearly not up to their caliber). About 6 people attended. (But I'm over that . . . .)  

    There were over 100 poster presentations. It was great to see such enthusiasm for scholarly activity among physicians early in their careers. (Full disclosure, I'm a physician too, although far from "early.")  

    Among the 100+ posters, There were 2 with scatterplots (one from the team I was consulting with.) The most common type of graph seemed to be pie charts---some of them monocolor ("100%"). Bar charts of means and counts were running a close second. A lot of 3-D embellishments in use also.

    This experience has gotten me thinking about ways to help this group improve their graphs. If I can devise and pitch an intervention, I'd like a way of assessing its effect (if any).  Can anyone point me to validated instruments for measuring the "quality" or "effectiveness" of a graphical display? I don't want this to be about my personal, idiosyncratic, and perhaps misguided aesthetic opinions.

    Thanks.



    ------------------------------
    Christopher Ryan
    Agency Statistical Consulting, LLC
    ------------------------------


  • 2.  RE: validated instrument for rating "quality" or "effectiveness" of graphical display of data

    Posted 7 days ago

    A big part of the problem is that 30 years ago Microsoft Office was forced upon the world.  So doctors, scientists, and engineers use business software for handling data and making graphs.   There are many authors who provide advice on graphs but a scale of do-this or don't-do-this is not available.  These authors argue among themselves so a lot is left to judgement. Still things like 3D bars are generally discouraged because they distort perception of numbers.  

    There is a distinction between infographics and statistical graphics and both have their place. I find that many people prefer bar charts or pie charts because they can't read line graphs. Doctors usually can read line graphs and scatter plots but apparently struggle with log scales, especially when used for drug concentration or rates.  I would think of the main issues in your niche and do a presentation or provide guidelines. 



    ------------------------------
    Georgette Asherman
    ------------------------------



  • 3.  RE: validated instrument for rating "quality" or "effectiveness" of graphical display of data

    Posted 5 days ago

    Georgette--

    I agree with you about the lasting adverse effects of Microsoft Office (in particular Excel), and the problems of business infographics versus scientific graphs. Kids in the US are socialized into MS (and nowadays Google sheets) as the way to make graphs. Seeing that output for 18+ years, they cannot imagine a better way. Sure, I suppose making in graphs in Excel was (perhaps?) better than pencil and paper. It empowered people to make graphs when they didn't (or thought they didn't) have any better way. It "democratized" graph-making. Maybe a useful thing? But it empowered people with no knowledge of graph-making to make a  lot of graphs. Not so useful a thing. This is similar to what happened with GIS software--taking the professional cartographer out of the loop enables lots of people to make lots of bad maps. One of the great things about R, Gnuplot, and other professional-grade software is that they incorportate decades of knowledge and experience in graph-making, so the defaults are pretty darn good. (Similar to LaTeX---two hundred years of typesetting knowledge made readily available to us non-experts.)



    ------------------------------
    Christopher Ryan
    Agency Statistical Consulting, LLC
    ------------------------------



  • 4.  RE: validated instrument for rating "quality" or "effectiveness" of graphical display of data

    Posted 7 days ago

    Not an instrument per se, but Tableau and its community have done a lot of research into the effectiveness of visualization and how the brain processes what we perceive visually. A lot of Tableau's standard options, settings, and color palettes reflect this, which sometimes goes against what we think is "better looking." Interestingly, you'll often hear arguments AGAINST pie charts as not a type easily processed by the brain and to use a bar chart instead. It is still available as an option in Tableau--I suppose they can't just not offer it because of its ubiquity. I find pie charts in Tableau to be "unfriendly" and rarely use them unless specifically required--perhaps their way of discouraging them? :-)

    I used to watch the Makeover Monday sessions, where people submit reimagined/reinterpreted visualizations of an existing public one every week. The hosts review some of them live, often to make a point, and the focus is essentially: is the story immediately perceivable? They are not mean, just often brutally honest, and the submitters (usually) know what they are getting into. I saw recently that the hosts have written a book stemming from these.



    ------------------------------
    Michiko Wolcott
    Principal Consultant
    Msight Analytics
    ------------------------------



  • 5.  RE: validated instrument for rating "quality" or "effectiveness" of graphical display of data

    Posted 7 days ago

    great question, I am not aware of a "validated" instrument. Possibly it may be useful for you to present a graph that leads astray and then show an improved graph. one potential example , I have colleagues who despise (the most polite word I can find after rejecting  the word frothing) "dynamite graphs".  Vertical bar graphs with say a "T" for the upper confidence limit. Looks sort of like a detonator for dynamite from a very old Hollywood movie

    https://techcommunity.microsoft.com/t5/excel/95-confidence-interval-to-bar-graph/m-p/334804?lightbox-message-images-335108=72849i542DBE4AF424F24

    https://techcommunity.microsoft.com/t5/image/serverpage/image-id/72849i542DBE4AF424F248/image-size/large?v=v2&px=999

    Permit me some historical context. As recently as the 1990's decade, we were ->forbidden<- to use SAS proc plot or gplot (a luxury at the time) to prepare graphs for inclusion in a submission or any other materials sent to FDA. That happened because one of our team members took a SAS proc plot output and tried to match the letters (SAS printed using letters A B, ....etc.) with the actual (pk type ) data and couldn't. Of course a letter is not a point on  graph.  That was escalated up the corporate executive food chain and the instruction forbidding use of proc plot anywhere  in our filing was sent back.  The concern was that an FDA reviewer might also try to match points on a graph with actual data and <by a chain of logic I fortunately have long ago forgotten> decided there was a risk of FDA refusing the entire filing we were preparing for the new drug because of a problem with a graph :)  I shelved my graph - is it turns out only for a decade or so. By coincidence I found that graph (in acetate)  in my notes about a year ago. I scanned those This was the type of graph we were forbidden to send to FDA https://flic.kr/p/2oWjjkh  I drew that graph , the color version was created with help from an expert  SAS programmer. An exception of some kind was made for the presentation at the Advisory meeting . Several of the SAS programmers were tasked with "validating " each graph that might be presented at advisory. 

    we were also forbidden to use one other alternative. For a hefty per plot fee ($$$$) one could arrange for a flat bed plotter from HP (we were near silicon valley and HP was just a few doors down the street) . That required use of an arcane plotting language unique to the flatbed plotter.  There was at most one (1) test plot- because those cost $$$$$ the same as the production plot.  Long ago forgotten.  What the flatbed plot could do was plot at a precisely defined x-y position on the flatbed.  in the present era, one can simply plot in R or SAS in an exact x-y  location in the plotting area.  To the best of my knowledge FDA has never refused a filing because of a plot. FDA will include plots in a drug label. For example labels have appeared with 'forest plots" and "waterfall plots" https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4093310/   FDA has organized a workshop about graphics. https://www.fda.gov/media/96653/download and I know of at least one pharma company that has routine meetings where data is presented in a graphical format.  The scientists in the laboratories  often prepared graphs and one package I recall hey used was sigmaplot. And some of those plots may have appeared in some reports sent to FDA.

    The only actual examples I know of researchers trying to read actual data values from a graph is in some meta-analyses. There are software packages one can purchase which let one use a stylus, on say a Kaplan Meier in a published article to extract the values for the KM curve. 

    You mentioned Cleveland and  on one occasion he and his collaborators used randomization in a design to evaluate a plot. (page 219 in the attached link)

    https://cloud.r-project.org/web/packages/ggcleveland/ggcleveland.pdf

      Please be sure to check Frank Harrell's notes, lectures and textbooks for advice on graph construction. for example the following is quite detailed.

    https://hbiostat.org/doc/graphscourse.pdf

    Hadley Wickham, developed ggplot ,and  likely has written more extensively on proper graph design

    from a google search, Hadley comments on 3d graphs in this interview

    https://simplystatistics.org/posts/2012-05-11-ha/

    - most important have fun!



    ------------------------------
    Chris Barker, Ph.D.
    Past Chair
    Statistical Consulting Section
    Consultant and
    Adjunct Associate Professor of Biostatistics
    www.barkerstats.com


    ---
    "In composition you have all the time you want to decide what to say in 15 seconds, in improvisation you have 15 seconds."
    -Steve Lacy
    ------------------------------



  • 6.  RE: validated instrument for rating "quality" or "effectiveness" of graphical display of data

    Posted 5 days ago

    Chris--

    That was my general approach. For example, I started with a vertical bar graph that I just made up, and turned it stepwise into a classic, sorted Cleveland dot plot: narrow the bars, then eliminate the bars, then rotate it 90 degrees, then sort by magnitude.

    We did something similar, starting with the Figure 6 from from Artur Bijoś, et al, Pediatric Radiology, 2007, 37:1247–1252.

    https://link.springer.com/article/10.1007/s00247-007-0659-y

    It's a 3-D vertical bar chart with (IMHO), the wrong bars next to each other, thus requiring the reader to exert extra cognitive effort to make the main comparison. We discussed several steps by which it could be improved, from the simple things (ditch the 3-D) to the more dramatic.

    We discussed "detonator plots" for sure!



    ------------------------------
    Christopher Ryan
    Agency Statistical Consulting, LLC
    ------------------------------



  • 7.  RE: validated instrument for rating "quality" or "effectiveness" of graphical display of data

    Posted 5 days ago

    You may want to reach out to the researchers highlighted in the Amstat News article from just this month:

    Understanding How Viewers Interpret and Interact with Statistical Charts | Amstat News

    and their article Testing Perceptual Accuracy in a U.S. General Population Survey Using Stacked Bar Charts (jds-online.org)

    Even if their instrument doesn't exactly fit your needs, they may have suggestions based on other instruments they looked at. Good luck!



    ------------------------------
    Elizabeth Eisenhauer
    Senior Statistician
    Westat
    ------------------------------