When a flowchart needs numbers: count each branch with a Sankey
A flowchart's decision diamond tells you the rule: if the answer is yes, go this way; if no, that way. It is silent on the question managers ask next, which is how many cases go each way. A Sankey diagram of the same decisions answers it, and it often changes which branch deserves attention.
The rule and the traffic
Keep the flowchart for the rule. It is the reference a new team member follows, and its decision branches should be labelled with their answers. Then draw the traffic separately: every decision becomes a node, every labelled branch becomes a flow, and the width of each flow is how many cases took it last month.
A worked example: support triage
A support flowchart asks two questions. Does a help article answer it? If yes, the customer is done. If no, the ticket goes to the support team. Can the first reply solve it? If yes, it is solved; if no, it is escalated to engineering, who either fix it or turn it into a bug report.
Now the month's numbers: 500 questions arrive. 180 are answered by a help article; 320 reach support. Of those, 200 are solved on the first reply and 120 are escalated. Of the escalations, 90 are solved by engineering and 30 become bug reports. Each node balances: 500 = 180 + 320, 320 = 200 + 120, 120 = 90 + 30.
The flowchart drew the escalation branch as one arrow among many. The Sankey shows that more than a third of everything reaching support (120 of 320) ends up with engineering, which is the number that justifies a better help article, a training session, or a fix.
Branches that loop back
Flowcharts often loop: a reopened ticket goes back to the queue. On the Sankey that is a flow back upstream, drawn as a return line under the diagram. Count it like any other flow, and remember it adds to the inflow of the node it returns to, so the node's totals include the rework.
Using the same words in both
Name the Sankey's nodes after the flowchart's outcomes ("Solved on first reply", "Escalated") rather than after the questions. A reader moving between the two diagrams then sees the same words in both, and the flowchart's branch labels become the Sankey's node names.
Frequently asked questions
Can a flowchart show how many cases take each branch?
Only as labels. A flowchart draws every branch the same width. A Sankey diagram of the same decisions draws each branch as wide as its count, which makes the busy and the leaking branches visible.
How do I turn flowchart decisions into a Sankey?
Make each decision's outcomes into nodes, each labelled branch into a flow, and put a period's case count on every flow. Every decision node should then balance: cases in equal cases out.
Try it on your own numbers
The editor is free and opens with a starter Sankey diagram. One row per node, and the diagram draws itself as you type. No signup required.
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