Value-stream mapping (VSM) is a lean manufacturing technique popularized in the 90s after its successful applications in the manufacturing industry with companies like Toyota. Since then, DevOps practitioners have shared these processes as it applies to software development. DevOps literature, such as the DevOps Handbook, suggests value stream maps inform the most critical areas of application for DevOps practices and technology. A VSM is also known as a material and information flow map. Using this map, you can identify areas of improvement and map your current state to your future state. If you’d like an in-depth look at VSM, I recommend “Value Stream Mapping: How to Visualize Work and Align Leadership for Organizational Transformation” written by Karen Martin and Mike Osterling. This blog post summarizes the key concepts of VSM and shares how you can use VSM within your IT organization.
Value Stream Map Symbols and Components
In a VSM, three types of flow deliver a product/service to a consumer. The flow of information, the flow of materials, and the flow of time. The flow of information goes from right to left in a VSM. And in contrast, the flow of information and time goes from left to right in a VSM. The illustration below shows the major components of a VSM.
Within the information section, the factory symbol denotes the customer, supplier, and any other entities. All VSMs have a customer and supplier specified. A truck indicates the frequency of delivery. Within the materials section, the process boxes host additional space to include information about the resources needed to complete a particular process. It can be advantageous to also track inventory between processes. This is often denoted by a triangle. We also have the arrows which can denote nonlinear/sequential relationships between processes. Lastly, a VSM has a flow of time to showcase lead times in the flow of materials and information.
These are the major components of a VSM. There may be additional VSM components and symbols that are helpful for more complex value stream exercises. This resource explains those VSM components in more detail.
Creating a Value Stream Map
Example Value Stream Map (edited from a Lucid Chart Template found here).
Here are the steps to creating a value stream map:
- Select the product or service you’d like to value stream map. Start with the most important / highest value proposition. Here I have Simple Service at the top center of my VSM.
- Start with your customers. The customer should drive the entire stream of value. In the example, a customer sends all their requests to a simple service.
- Define your start and end processes. Scope your VSM with a start and end trigger. Here I have prioritizing reported bugs as my starting event. Likewise, deploying the feature is my final event.
- Include information flow. Reach that information flows from right to left in a VSM. In my example, I have “Feature Requests” as the triggers to my start process. Once code has made it to production, I have “Ship the Service” as my final flow of information.
- Fill in the remaining processes. In my example, I have the components of a standard software lifecycle: develop, build, test, and deploy. Here I could also add in counts of inventory or average quantity between processes.
- Gather process data. I am including who is involved in each process along with the tools they use. Be objective in this step and the following one. The goal is to capture the current state.
- Create the timeline. Here I am mapping current metrics on each process. There are three standard metrics used in VSM. Lead Time, Process Time, Percent Complete & Accurate. Lead time is the elapsed time or time from initiating the phase to completing it. The processing time is the amount of time it takes to handle the said request. And Percent Compete&Accurate (%C&A or PCA) is the percentage occurrence where the finished output was correct according to the requirements of the customer of the process.
Evaluating a Value Stream Map
Now that we have a VSM let’s discuss how to analyze it. If you are not adding value to your end customer, you are adding to the cost of production. Value stream management practices encourages organizations to focus on the flow of value.
Organizations will look at a Value Stream Map to consider the performance of entire systems. Starting with a single stream of value can help ease other parts of your organization into adopting new ideas and practices.
Flow refers to the flow of work in your value stream. Work can come from features requests, requirements, defects, and or support tickets. The goal is to ensure that the value stream is always moving forward. Some things that can affect flow include:
- Changing priorities and task switching,
- Lack of visibility around problems and processes,
- Long development cycles,
- And not getting code to higher environments
A book titled Team Topologies authored by Matthew Skelton and Manuel Pais share a few more obstacles to flow. https://teamtopologies.com/
Here is a guide to improving the flow of work within a value stream. It involves creating a dedicated transformation team that’s held “accountable for achieving a clearly defined, measurable, system-level result (e.g., reduce the deployment lead time from “code committed into version control to successfully running in production” by 50%).” This dedicated team should have the resources and freedom to utilize the different DevOps practices to achieve the results.
There are also eight types of waste defined through the lean manufacturing movement. The diagram below describes these types of waste.
The 8 Types of Waste. (Image source: https://theleanway.net/The-8-Wastes-of-Lean)
If we’d like to minimize in our software delivery processes we need to consider how to manage these findings.
Here are some more ways to look at a Value Stream Maps.
- Optimize Value Streams through Process: Look to see if your process is of the following characteristics: valuable(does the customer need this), capable(quality results), available(minimal downtimes), adequate(meets demands), flexible(can be switched or configured).
- Focus on flow: Is flow continuous or stagnate? Consider your quantity levels. In the earlier VSM example, the flow could stagnate if there are no feature requests. Likewise, if you have too many features developed, your QA process may need more scaling. Identify areas where your value stream is suffering, if stagnation exists.
- Analyze the flow of information: Is it a push or pull model? In push models, the supplier supplies customers with features and deliverables. In a pull model, the customer is requesting those features. It’s important to have the right balance to ensure you’re not overtaxing specific job functions and processes in your value stream.
A well-executed VSM workshop gives those in the room the opportunity to champion change. Maybe you’re using an outdated tool for a certain process. A VSM workshop invites critical stakeholders to come and challenges areas of your value stream.
Harness Your Value Stream
Every organization has a process for delivering their product or service to their customers. Value-stream mapping allows you to optimize your flow of materials and information by lowering costs and improving value adds. This blog posts shares some tips for navigating your DevOps journey through Value stream management techniques such as Value Stream Mapping.