The mean absolute deviation or MAD as it is often abbreviated, of a dataset is the average or "mean" distance between each data point from the data set and the mean/average.  This will give you an idea of the amount of variability in a dataset.  MAD can be calculated from both observations and the arithmetic average (mean) of those observations.  Another option when calculating MAD is to calculate based on actual data minus forecasted data.  If forecasting or being used for future analysis you can apply different weights to your forecast or use exponential smoothing in an attempt to make your forecast more accurate.  In most cases however mean absolute deviation uses actual data.

  The house of Toyota is a graphical representation of the Toyota Production System depicted in the form of a house.  Taiichi Ohno was given credit for much of the systems development.  The Toyota Production System works together with 5 key elements:​

  A push system is the production or performance of any item or activity performed at required times by a given schedule that has been planned in advance.  Many push systems are built mainly to forecast.  Push systems can also include issuing material or performing an activity based on a schedule rather than need.  Push systems create excess inventory which is one of the 8 forms of waste.  

  A pull system is a technique used to produce only what has a demand attached to it.  Pull systems are also used to replace inventory items or information which may have been taken to fulfill a demand.  Pull systems use triggers to notify individuals when a demand or a need has been generated for the part or service.  

  The 5 core principles of a Lean Organization were first written about in a book entitled:  Lean Thinking by James P. Womack and Daniel T. Jones.  The 5 core principles are widely accepted as a means implementing and establishing a lean organization.  The 5 core principles have been adapted from the 5 original principles that were defined by Dr. Womack and Daniel T. Jones:​​ 

  A changeover is the work required to change a specific machine, resource, work center or line from making the last good piece of an item to making the first good piece of another item.  That means that if the first good piece after the changeover is not good the changeover is not complete.  

  Variation is the term used to describe the consistency of a processes outputs.  Reducing variation is one of the most important objectives in Lean and Six Sigma.

  Takt time is a German phrase for the baton the conductor uses to set the tempo of an orchestra.  In Lean and Six Sigma applications Takt time refers to the rate at which products, information and/or services need to be completed in, to keep up with customer demand.  ​Much like the pulse of a heart rate, Takt time tells us whether we are beating at a healthy rate or we are falling behind.

Managing inventory would be impossible without a means to track how much inventory is on hand and if it is an appropriate amount of inventory.  With that being said, the days of supply metric is a useful metric that can show an organization how many days their existing inventory will last before it reaches zero or drops into their safety stocks.

  A forecast is a prediction of something to come or in the future.  A forecast would take place before any type of action or activity happens.  Forecasts are almost always wrong but they can be used to define a hope-for, goal, target or condition that you believe is attainable based on analysis and assessment.

  A bottleneck is the term used for any function, department, resource or facility whose needed capacity is less than the demand being placed upon it.

This type of Kanban is probably one of the most used and the most basic types of kanban. The card is used in manufacturing and software development to trigger production. 

  Demand is an economic principle that describes a consumer's desire or willingness for a specific good or service. Holding all other factors constant, an increase in the price of a good or service will decrease demand, and vice versa.  Demand can also be defined as a quantity of a commodity or service which is either wanted or needed.

A countermeasure is a measure or action that is taken to counter or offset another one.   ​

  Internal Move kanbans are essentially permission to retrieve or move materials or information.  The move kanban authorizes one point of a process to get what they need and move it.  Many cards will show the consuming location and the supplying location so that the person moving the tagged item knows where to move too.  Let’s look at a very basic example of how the move kanban works.