====Lag Source====

All lag happens for a reason. For [[data-driven lag|data-driven lag]], you compensate for lag using a data point. This data point is called the **Source of Lag**, since it measures the //reason the lag exists// (ie. the distance between sensors).

This data point will almost always be either a **counter** or a **rate**.

Rate examples include...

   * Production Line Speed
   * Flow Rate
   * Number of Products per Second*

Counter examples include...

    * Distance Total
    * Flow Total
    * Production KPI (ie. Products Produced this Hour*)

//*: For metrics such as 'products per second' or 'products this hour', we assume that each product is the same size/shape/distance apart//.

By reviewing the value of this point, we can convert a particular amount (which we call a //distance//) into a time-difference, by calculating how long it to either //count// or //total// that much.

===Example===

For example, you may a conveyor system with two items 50m apart.

In this case, the **source of our lag** is the //speed of the conveyor//, and the **distance** between the two sensors is //50m//.

We calculate the amount of lag between the two sensors by back-calculating how long it took 50m to pass based on the conveyor speed.