Also known as Time Value Chart.
A time value map is a graphical representation of the value-added and non-value-added time in a process. It focuses on what adds value to a business process as perceived by the customer. The aim is to make the process more efficient while maximizing the value delivered to the customer. It is considered one of the many Lean tools that will help to identify and analyze waste and non-value-added activities within your processes.
This tool is mainly used to monitor how much time is wasted starting from the beginning of the process until product or service delivery. It allows the identification of waste related to time, especially waiting and unnecessary delays. You need to examine how long it takes to complete each activity within a process. This involves recording the processing (or touch) time as well as the queue (or waiting) time, idle time, inspection time, etc. Such information can be obtained from the timeline of the value stream map or after conducting a process chart exercise.
Each activity within a process can be classified into one of three categories:
In a time value map, all activities are plotted as bars proportional to their time values along a horizontal timeline. Activities that add value to the customer are plotted above the timeline whereas activities that do not add value to the customer are plotted below the timeline. You may use the traffic light colors to convey the map more clearly.
Creating a Time Value Map
- Make sure everyone is clear on what process to analyze.
- Draw the process timeline at the center of a whiteboard or flipchart.
- Specify the start and end times, total cycle time, cycle time intervals, and the queue times between activities.
- Draw bars to represent the value-added activities time above the timeline.
- Draw bars to represent the non-value-added activities time below the timeline.
- Calculate the total value-added time, total non-value-added time, and value stream ratio.
- Implement projects and systems to eliminate or reduce the non-value-added activities and decrease the overall waiting time.
Example – Patient Flow Process
In this example, we will be analyzing and recording the time taken to perform each activity for the patient flow process in a clinic. The process begins when the patient enters the clinic and ends when he/she exits the clinic. Note that time information was taken from this process chart exercise.
Note that delays, waiting and idle time could be represented as blank spaces or gaps between the bars.
A time value map can also be represented in the following format where all bars are parallel to each other.
Later on and when you better understand the process, some activities should become obvious candidates for elimination or modification.
The scale of the timeline can either be intervals of the cycle time (in seconds, minutes, hours, etc.), or the actual time of a day.
There are many tools that can help you to monitor how much time is wasted in your processes. The simplest way is to use this template.
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