Cycle time is defined here as the difference between the exit time and the corresponding entry time of a card, i.e the time spent in the selected region of the value-stream during that visit. In a normal situation, as cards move forward from left to right, a card will travel through the selected region of the value-stream only once. However, if we allow cards to move back, or move between different value-streams it is possible for a card to visit multiple time. In such situations, the scatter plot will show multiple instances of the card, once for each visit.
Cycle Time Scatter Plot
The x-axis represents time, the y-axis represents cycle time (in units selected in Time unit Each dot represents a card whose x position is determined by its exit time, and y position is determined by the cycle time. The dots are colored based on the value of Color by attribute of the card. Different shapes indicate the type of exit:
- Circle: move forward or is archived
- Triangle: move back
- Square: move to another value stream
- Diamond: cards that were deleted or discarded
On the right of the scatter plot we have box-and-whisker plot as defined by John W. Tukey.
Box-plot provides a non-parametric characterization of data without making any assumptions of the underlying distribution. The bottom and top of the box are first and third quartiles, and the line inside the box is the second quartile (the median). The lower whiskers are drawn to the lowest datum still within the 1.5 IRQ ( interquartile range: q3 – q1) of the lower quartile, and the upper whisker is the highest datum still within the 1.5 IRQ of the upper quartile.
Box-and-whisker plot is often used to identify outliers in place of 3 sigmas when the underlying distribution is unknown. For comparison, for normal distribution, 6 sigma range represents 99.73% of the total area, whereas box-and-whisker range represents 99.3% of the area. The actual area being covered, however, depends on the nature of the distribution.
Calculation Logic for the Scatter Plot
Cards that exit the selected region of the value-stream during the time interval selected in the Temporal Range Filter, pass the filtering criteria and have entry time defined form the basis for cycle time calculation. These cards are plotted on the chart based on their exit time (x-axis) and cycle time (y-axis).
Cycle Time Histogram
Get to know more about the Cycle Time Histogram here.
Card Distribution Pie Chart
A pie chart showing the breakdown of cards used in cycle time calculation colored by the Color by attribute of the card.
Calculation Logic for the Card Distribution
Cards that exit the selected region of the value stream during the time interval selected in the Temporal Range Filter, pass the filtering criteria and have entry time defined form the basis for cycle time calculation. For the pie chart, these cards are grouped by Color by attribute to form segments of the pie. The total number is shown at the center of the pie.