Value Stream Mapping: A Guide to What it is and How to Use It
Want to know what Value Stream Mapping is and how to use it to increase productivity? This guide will show you everything you need, to learn and implement it. But first, let’s cut to the chase and answer the number one question…
What is Value Stream Mapping? Value Stream Mapping (VSM) is a lean manufacturing tool that allows you to see all the steps involved in a group of processes. It does it in such a way that everyone can easily see where improvements can be made to increase efficiency and throughput, and therefore reduce lead-time and costs.
The general steps in creating a VSM are:
Step 1: Create a current state value stream map – How the processes work as of now and then identify where the waste is
Step 2: Redesign processes and create a future state value stream map – How things will be in 9-12 months time based on new and improved ways of working
Step 3: Create an action plan to enable you to move from the current state to the future state version
Step 4: Agree action owners and time-scales and then implement the action plan
That said, there are a lot of details to getting a value stream map right. It takes a mixture of good knowledge, acquired via reading some decent books and doing a few value stream maps yourself to get the experience.
We’ll go through the what’s, why and how of value stream mapping, so you can get on the right track, fast.
The History of Value Stream Mapping
Although Toyota had been mapping, visualising waste and then identifying improvements within their business for years, it was John Shook and Mike Rother in their book “Learning to See,” which brought the term Value Stream Mapping to the world, and showed us the framework to do it.
In 1998, John teamed up with Mike at the University of Michigan to break apart Toyota’s method of how they visualise their work-flow.
They then pieced it back together as a fully working method found in the Learning to See book.
Nowadays, there are hundreds if not thousands of books written around VSMs, all originating from this ground breaking book.
In fact, Value Stream Mapping provided such a comprehensive shift in thinking, that it’s the cornerstone to making lean improvements. Everything centres around creating the map first – Only once you can see the waste, you can then improve it.
The Benefits of Value Stream Mapping
1. Visualise Improvements on One Document
A VSM allows everyone to see the steps within a given set of processes and how everything works… All on one display. There’s no comprehensive reports to type out – just a simple ‘one page’ VSM, in a simple to see format, using standard tools and symbols.
2. Helps Identify Waste
One of the main elements of lean and continuous improvement is to strip waste out of processes. It’s this waste (or non value added) work content that increases cost, and lead time.
Waste are the elements that will slow down your processes. They’re the delays and waiting… the checking and cross checking… the organising and planning….poor quality… the missed opportunities…the poor productivity on machines…and so on.
Once you can see this waste, you can begin to improve things.
3. You can See Bottlenecks
Bottlenecks are areas in a process where work just builds up and causes blockages in flow of information and product. Some examples could be:
- One process is faster than another – it’s the slowest process which will slow down the whole value stream as others wait to be supplied
- In-trays – work tends to get stored up and then batch processed, which then starves the value stream of regular work. This can be in office and production
- Shared resource – one equipment processes many different jobs which can slow everything down and create long queues
Just like waste, bottlenecks must be seen and then improved. A VSM shows you instantly where work is built up and why. This then means that it’s obvious to see what needs fixing.
4. Standard Way of Seeing a Complete Set of Processes
If everyone is trained in Value Stream Mapping, and they understand the symbols used, then it’s really easy to see where the waste is in all parts of the business. And by everyone.
All employees can get to work to improve their value streams – working to the same improvement goals (which have been defined on the value stream map).
5. Allows You to Re-design a Complete Value Stream Before you Make Improvements
Imagine being able to see and define how processes and systems should work, before any improvement has been made?
Imagine if you knew that in order to achieve 50% more output, you needed one piece of equipment to improve its productivity by 1 hour a day?
What if you could increase productivity in assembly by 25%, then you wouldn’t need any overtime?
Imagine if you could also redesign flow in the office to turn proposals around within 24 hours, instead of the current 4 days?
And by creating a work cell in finishing, you could reduce lead time from 3 days to 3 hours?
What if all of these things needed to happen within the same value stream? And if you could achieve this, then you’d offer more value than your competitors?
By creating a VSM, you’ll be able to visualise all of these improvements working together, to benefit the business. You can then align these projects for the benefit of the value stream.
This then not only allows you to picture what your value stream could look like in the future, but also show you what must be done to make it happen.
6. Improves Productivity, Leadtime and Quality
With value stream mapping, the aim is to improve flow of information and product through the business. By default, when you do this, you can create huge step-change improvements in productivity and quality. The by-product of this is vast reductions of leadtime to your customers.
From my personal experience, it’s not uncommon to redesign complete end-to-end value streams, that have achieved:
- Double the output with no extra resource
- Taken Lead-time from months to days
- Improved quality of information being passed on right-first-time, by over 100%
How Value Stream Mapping Fits Within Lean
A VSM creates the strategic document and plan to make lean happen in a joined up way. Without it, you’ll normally find that you can make improvements, but they’re not aligned.
Without a future state VSM having been created, you run a big risk of making silo improvements in one department or area, but not linking this to the next process or the bigger picture (as per our previous bullet point).
VSMs bring improvements across the business, whilst using the employees to make it happen, all targeted to the same improvement goals.
A Value Stream Map is not something created by one person in a dimly lit room, hidden away for weeks… It’s a dynamic tool that everyone plays a part in:
- Collecting information to support the mapping
- Adding their ideas to make concerted improvements
- Identifying their own personal observations and pain points
- Agreeing actions and timescales to co-ordinate improvements
That’s why a VSM is high up on the lean agenda. It’s both a tool to target what needs to be done and where across the value stream, and also facilitating teamwork and ideas generation.
The Five Key Principles of Lean
That said, Daniel T. Jones and James P. Womack defined the 5 key pillars of lean.
- Understand value in the eyes of the customer – What is it that they want?
- Map the value stream – This is where our trusted VSM comes in
- Make the Value Stream flow by removing waste
- Create Pull so you can link processes together and make to order
- Continuously improve using lean management and PDCA
Notice that value stream mapping performs a very important role in these five steps:
- It allows us to understand what the customer wants (step 1)
- To walk our processes and see how things actually get done (step 2)
- To document this on a standard template
- To then use waste elimination, pull and continuous improvement to improve its performance (steps 3,4 and 5)
That’s why VSMs are at the heart of lean. Everything in the 5 principles of lean should be defined on a Value stream Map.
Here’s how Value stream Mapping brings it all together. The VSM is the vehicle to facilitate all 6 steps. I Call it the 6 golden Steps to Value Stream Mapping:
Horses for Courses
Value stream maps are not just a plug and play tool. You’ll need to use the right type to suit what you’re analysing.
For instance, you may wish to use a VSM in the health care, a service business, a continuous manufacturing process, or even make to order manufacturing.
How you create your map and see the waste will be slightly different to suit the environment you’re operating in.
I create different VSMs for different applications. Here’s what I mean:
The above version is what I use for manufacturing businesses. It’s a classic VSM and clearly shows:
- The suppliers on the left of the map
- Product flow at the bottom, from left to right
- The customer on the right
- Information flow at the top of the map
Business Process Value Stream Mapping
This version of a VSM is what I use for purely service based businesses. The format is slightly different, although it still shows some similarities:
- The map proceeds from left to right
- The customer is on the right of the map
- Each process has a data box, identifying it’s critical metrics
- The key measures are total lead time, total process time and quality (% complete and accurate), The same is for the manufacturing map, but presented in a slightly different way.
Differences in Display, But Similar End Results
Nevertheless, Each VSM still provides the team with the same process and outcome, which is:
- Creating a current state
- Designing a future state
- Defining and quantifying the improvements in quality, cost and delivery
- Creating an action plan to achieve the future state
- All of which is about improve right-first-time quality and reduction in leadtime.
That’s effectively what a VSM is there to provide.
People’s Perspective Have an Impact, Too
When I first started value stream mapping, i was so concerned about getting the VSM to look “right”, like it in the books, that i forgot what the main goal was. It’s quite simply to see and visualise waste.
Then it dawned on me.
As long as you use the common symbols and follow the VSM process, there may be some subtle differences on how they look from person to person, but the important information should be similar.
To see the waste and improve lead time and quality. This is what counts.
Value Stream Mapping Symbols
A value stream map has been designed to be simple, so everyone can understand it quickly and spend time making improvements.
For this reason, there are a number of symbols that are commonly used, to show many different observations in a map.
The folks at Six Sigma Blackbelt kindly provide you Excel and A3 Printable Versions to download.
Here are the common value stream mapping icons that you should be using and what they mean:
Examples of Value Stream Maps
At this point, it makes sense to show you some VSMs, so you can get a feel of what they look like and their applications in the real world.
Key Similarities Across VSMs
It’s not just a case of documenting processes. Flowcharts do that. Value stream maps are powerful because they link flow analysis with performance analysis.
This performance is measured in:
- Total Cycle Time – How long it takes to process the Value Added Work
- The Total Lead-time – How long it takes for the customer to receive their product or service they ordered. This includes the cycle time and the non value added activities. You’ll often find that total cycle time across the value stream is in seconds or minutes and total lead time is in weeks or months.
- Total Process Efficiency – This is the ratio between Value Added Time (or cycle time) and Total Lead time
- Quality – How much information and product is produced and passed on right first time? In a business process VSM, this is often called % complete and accurate (C&A).
In the business process VSMs, you’ll typically measure Process Time, Lead Time and %Complete and Accurate (C&A)
There’s slightly more information in the manufacturing data box, but there are similarities: Cycle time (or process time), Quality (Right First Time %). We normally want to measure other things like how long it takes to set up a machine, and how long it actually runs for.
The Difference Between a Process Map and a VSM
At this point, most people ask what’s the difference between a process map and a value stream map?
The answer is based on the level you’re mapping.
By this i mean the detail.
A VSM is a top level view. It’s like you’re standing there over the business and seeing the processes and how they work as a whole. It’s not detailed, but just enough to give us a picture of what’s happening.
The higher up you go, the less detail you document. And the reverse is true: The lower you go, the more detail you’ll map.
A VSM merely shows the waste and summarised metrics of each process step. In fact at the VSM level, one process may have several different steps within.
If you want more detail, then you should map a particular process. This is where a Process Map comes in.
Often Process maps happen as part of getting more information to support the main VSM overview.
The Components of a Value Stream Map
- We’ve identified the standard symbols.
- We’ve also identified the main steps, and what VSMs typically look like.
There are some key elements to drawing your Value Stream Map.
Step 1: Start with the customer. This goes at the top right of our map, so add the icon here.
What do they want? When and how often? This information is added under or adjacent to the customer icon.
Step 2: Define the Process at a top level perspective. Each box represents the summary of each process. Remember, every process step may involve several lower-level steps. We want to summarise here.
Step 3: Add inventory build ups between steps. They can be seen as triangles. They’re important to highlight because this symbol shows bottlenecks and that inventory is being built up and not controlled.
By this i mean, there’s no link between processes to identify what to make and when.
Step 4: Add the Suppliers’ box to the left of the map. Include order frequencies and also how much raw material or supplying material you have.
Step 5: Now define the information flow. Map the information and how it triggers from one process to the next; where does it come from? What information is sent from the process to the next step?
This is mapped at the top of the Value Stream Map for manufacturing VSMs, otherwise it forms the main databoxes for business processes.
Step 6: Collect data for each process. These form the summarised data for each main production step.
The information here is summarised as:
- The cycle time
- The number of shifts at each stage
- The Change over time
- The Uptime of the equipment (Efficiency)
- Inventory levels
- Batch sizes
- Number of people in the process
- Quality levels (right first time %)
How to Read a Current State Value Stream Map
There are some fundamental things to look for in a current state VSM.
In most current state maps (non lean ones), you’ll find that the supervisor often prints out a work-to list for each production process to work through. This in itself promotes a silo thinking. “As long as i get through my list…” is not the way. Processes need to be linked and ideally one point in the value stream should be scheduled. All other steps should be linked, so they can work to that pace and mix of work.
These are those dreaded triangle symbols. A future state map should have no uncontrolled inventory symbols. If there is inventory, then it’s controlled in much the same as we link processes through Pull.
Excessive Raw Material
Having too much inventory sitting around the warehouse is not conducive to lean. It fills up space pretty quickly, and is a heavy price to pay in cash. In a current state map, we don’t want to see lots of raw material sitting around. Little and often is the way forward.
How much is too much? A rule of thumb – no more than 1 month should be sitting around for the stuff that’s regularly used. If it’s local supplier, try to aim for a week or even days.
Large Batch Sizes
Ideally, you want to process in as small-a-batch size as possible.
If your facility is releasing in large batches, it only aids to creating bottlenecks.
Other work waits until it’s their turn in the queue. If your current state value stream is telling you that large batches are the current norm, ask how you can reduce them. Each reduction increases productivity and throughput of work.
Excessive Changeover Times and Downtime of Equipment
If machines are not being utilised, they can’t process as much output.
And if your machines are spending excessive time changing over from one job to the next, you’re not going to be able to reduce your batch sizes.
You need to work on quick changeovers and reducing set-up times. When you do, batch sizes can be reduced.
Long set ups provide a goldmine of opportunity.
Poor Information Flow
Are there any duplicated information?
Is the information not right first time?
Are there parts where information is batched?
All these can be improved. When checking how the information flows from order to scheduling production, ensure that it’s efficient and effective.
The golden rule i use is this: If something happens every day and is highly repeatable, then it should work like clockwork. This means no extraneous decision making and thinking. The processes should run the system, not the reliance on specific people.