Protobi

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<p>Flow diagrams can be a good way to visualize relationships between variables,
like progression of treatment regimens by line of therapy.</p>
<p>One type of flow diagram is the <a href="https://en.wikipedia.org/wiki/Sankey_diagram">Sankey diagram</a>
where the width of the arrows is proportional to quantity.  Here's how to create one in Protobi...</p>
<p><img src="/images/blog/2018-08-31-sankey/flow-mfr-color.png"  style="margin: 0 auto; width:480px; max-width:480px; display: block;vertical-align:top"></p>

<h2 id="create-a-group-of-categorical-variables">Create a group of categorical variables</h2>
<p>There are a few ways to create Sankey Diagrams in Protobi.  One way
is from an ordinary crosstab.  Another is to identify a sequence of categorical variables and place them into 
a distinct group. </p>
<p>For instance, for a patient chart audit  you might choose
first-line, second-line and third-line treatment regimens.
For this example we'll use three variables from an industrial survey screener: Region, Industry and Role:</p>
<p><img src="/images/blog/2018-08-31-sankey/flow-mfr-group.png"  style="margin: 0 auto; width:600px; max-width:600px; display: block;vertical-align:top"></p>
<p>A simple way to create a group is to press the "+" tab to create a new tab, 
and hold the shift key while dragging elements from the tree into the new tab.</p>
<h2 id="set-chart-type">Set chart type</h2>
<p>Press the square edit icon to bring up the chart dialog, and choose "Sankey":</p>
<p><img src="/images/blog/2018-08-31-sankey/flow-gg-dialog.png"  style="margin: 0 auto; width:360px; max-width:360px; display: block;vertical-align:top"></p>
<h2 id="resize-and-organize">Resize and organize</h2>
<p>Voilá, you now have a new flow diagram.  You can drag the blue resize handle 
to resize the chart.  You can drag the squares to re-order them vertically.</p>
<p><img src="/images/blog/2018-08-31-sankey/flow-mfr-bw-selected.png"  style="margin: 0 auto; width:480px; max-width:480px; display: block;vertical-align:top"></p>
<p>If the parent group has a format specified that applies to all the child elements,
Protobi will choose initial colors automatically from the default theme.
Here however we created a new group, and can choose the colors explicitly.</p>
<p>Press the square edit icon and choose "Edit JSON..." from the context menu.
Create a new entry <code>"colors": { "key": "color", ...}</code> to specify colors for 
each child value.</p>
<p><img src="/images/blog/2018-08-31-sankey/flow-mfr-json.png"  style="margin: 0 auto; width:480px; max-width:480px; display: block;vertical-align:top"></p>
<h2 id="finished-diagram">Finished diagram</h2>
<p>Below is the finished diagram:
<br/><br/>
<img src="/images/blog/2018-08-31-sankey/flow-mfr-color.png"  style="margin: 0 auto; width:480px; max-width:480px; display: block;vertical-align:top"></p>
<p>Here we can visually see a few interesting features:</p>
<ul>
<li>respondents in "Healthcare" are exclusively from North America</li>
<li>respondents from China are most often in "Manufacturing"</li>
<li>sales people are most often in "Retail Trade"</li>
</ul>

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