The sigmoid function is a type of mathematical equation that mimics an S-shape curve and is often used in visualizations such as Sankey Diagrams, Ranking Visualizations, Node-Link Diagrams, and many others.By creating additional data points within Tableau for each 'real' data point, math can be used to implement the sigmoid function using data to define the starting and ending point for the curve. The following sequence of examples shows how the sigmoid curve can by implemented in tableau and a few examples of it in use.
The animation below shows a single sigmoid curve using a logistic function. In the text below, the value of t is shown, a number from -6 to 6 representing how far through the curve the animation is. This value is what is used to determine the coordinates for intermediary values in Tableau.