<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On May 14, 2020, at 12:21 AM, Willem Ferguson via subsurface <<a href="mailto:subsurface@subsurface-divelog.org" class="">subsurface@subsurface-divelog.org</a>> wrote:</div><div class=""><div class=""><p class="">I must admit that I do not like any of these three
representations. They are inappropriate and inaccurate, leading to
misinterpretation.<br class="">
</p><p class="">The top graph is normally used to indicate trends in three
*independent* variables that may or may not be correlated. In the
dive the data represent a *single* variable with its min and max
values.</p><p class="">The middle graph is a histogram that would normally also
represent three *independent* variables that have been sampled on
the same x-axis scale. Again, in the dive case the min and max
values represent the *same* variable.</p><p class="">The bottom graph is normally used to indicate the proportion of a
total that is formed by a specific component. In the case of this
specific graph, the median would be indicated by the height of the
orange bar (i.e. vertical distance between the grey-orange border
and the orange/blue border). The max would be indicated by the
height of the blue part of the graph, etc. Clearly this is not
what is meant.</p></div></div></blockquote><div><br class=""></div><div>I agree that the middle and bottom option aren't adequate for the purpose.</div><br class=""><blockquote type="cite" class=""><div class=""><div class=""><p class="">I want to make a call that, if we are dealing with representing
statistics, we actually use the proper statistics representations
that we are all used to. Most likely that is either some variant
of a box and whiskers diagram or a vertical bar chart with error
bars. If these diagrams have been shown once to an uninformed
person, the interpretation will always be easy. Lets use diagrams
for what they are meant to convey and not use a sports car to
drive offroad. We do not want any statistics related to Subsurface
to be presented in an unprofessional and inappropriate way.<br class=""></p></div></div></blockquote><div><br class=""></div><div>I think we have a couple of choices here. Build the right tool for the statistics professional. Or build something that helps make the statistics accessible to most of our users.</div><div>The more I think about these options, the more I think that the statistics professional is best served by using R and creating the views that they are looking for - because this will become a never ending "bring me another rock because I want to see things THIS way".</div><div><br class=""></div><div>So box and whiskers are out, because the vast majority of our audience has a hard time understanding the difference between a mean and a median, and between naive gas pressure calculations and actually accurate math (I get at least two emails a month stating that our SAC rates are wrong).</div><div><br class=""></div><div>Now as for which specific graph to use and which one is easier for users WITHOUT A BACKGROUND IN STATISTICS to grasp, I am certainly open to more input here. Ideally input that is based on actual feedback from such users or presentations about data accessibility and visualization. I found the video that Pedro shared rather compelling (especially if played at 1.25x speed because the presenter is taking his time). Which is why I am leaning towards a line graph, but I certainly could see floating bars with a marker for the mean.</div><br class=""><blockquote type="cite" class=""><div class=""><div class=""><p class="">
</p><p class="">As far as the horizontal graphs are concerned, they have a place,
but we need to understand where they come from, and that is from
the old days when we tried to print graphs on a mainframe line
printer that could not print characters vertically. The
conventional way to represent histograms or bar charts is in the
vertical way *unless there is good reason to do otherwise*. These
days there is no problem in printing labels vertically. To have a
horizontal bar graph with depth measurements along the vertical
axis is just totally unorthodox and not up to modern standards.</p></div></div></blockquote><div><br class=""></div><div>Willem, those are some very strong statements that initially provoked a rather negative reaction in me. Calling someone else's proposal "not up to modern standards" feels borderline insulting.</div><div>As a matter of fact, yes we can show vertical labels. They are also a complete pain to read. I would argue that the readability of a horizontal chart is actually much better than the vertical one that you so strongly argue for.</div><div>I did a quick survey of some of the other dive logs that have screen shots of their statistics pages up on their web sites. And they seem to be about equally split between the two different approaches.</div></div><div><br class=""></div><div>To me in the end this doesn't really matter. I don't think I'd ever use this other than to test that it works. Which is true for two thirds, actually, more likely 80% of the features in Subsurface.</div><div>What I do care about is that we continue to build something that stays maintainable, stays usable, and serves the need of a broad user base. That's why I refuse the frequent attempts to turn Subsurface into an asset management tool. And that's why I will gently push back to attempts to turn Subsurface into tool for statisticians. There are great tools for those purposes. Use them.</div><div><br class=""></div><div>/D</div><div><br class=""></div></body></html>