# Articles

## Pitch: Takt Image Math

Pitch is a representation of takt image - a visual and often audible management timeframe that lean practitioners use to pace and monitor value stream performance. It is typically driven by, and linked to, a value stream or line’s pacemaker process. Pitch performance is routinely tracked and reinforced with plan vs actual charts (a.k.a. production analysis boards), digital displays, lines that are “pulsed” or indexed every time interval, etc.

## Demand Segmentation Graph

An interesting pattern often emerges when you graph the coefficient of variation (Cv) vs. volume of a process time series.

## Value Stream Map Lead Time Q&A

Recently a reader posed the following value stream mapping lead time related question(s). My experience, after facilitating more value stream mapping activities than I care to remember, is that it's not an uncommon question. In fact, it's a very good question.

I provided a quick answer...supplemented by a very sophisticated graphic (recently enhanced, in red, based on a comment from Sandor).

## Summation notation and sizing the kanban bus route

Σ or Sigma is the Greek upper case capital letter S and is used in mathematics to represent summation or addition of a series of elements or set of data values.

x_{1}, x_{2}, x_{3}, ... x_{n} is a set of numbers. x_{1} is the first number in the set, x_{i} is the 'i'th number, x_{n} is the last of n numbers.

Elements can be simply adding up a set, or more involved such as summing squares or other algebraic equations.

## Square root law of inventory - application

Haruhiko 'Harry' Matsumura wrote a comment "Hi, Sirs, Regarding square root law of inventory, I prepared a useful kaizen proposal paper to give my clients to address stock reduction by means of location."

## Machine Cycle Time

Machine cycle time (*T _{cm}*) represents the actual time it takes for one machine to complete all of its operations on one piece, product, patient, file, etc.