A Value Stream is an illustration of the key steps in a process. It helps show the high-level process flow and identify improvement areas.
A Value Stream Map (VSM) is used within Lean practice to identify waste and activity which does and does not add value to the customer. Non-value add activity can be categorised by activity a customer is not prepared to pay for, such as a bottle neck in a delivery or service.
The VSM provides a place to capture data to demonstrate current cycle-times within each process step, and identify areas where these could be reduced. The benefit of mapping a value stream comes from what it shows you in terms of bottlenecks or any other inhibitors to the smooth flow of the process. Illustrated effectively, it can provide clear visual evidence backed up with data, to help you target the relevant re-design or optimisation of the process itself.
Determine the start and end of a process before you set out to map it. It sounds obvious, but imaging mapping the value stream in a coffee shop. Do you start from when the customer enters the store, or when they join the queue? A value stream of a coffee shop process may start with the customer entering the store, and end with them leaving the store with their drink. What happens in-between can be broken down into key steps, such as joining the queue, ordering a drink, paying for the drink, and waiting for the drink to be delivered.
Agreeing the key steps enables you to collect relevant data to record the time, resource and effort taken within each. Data for the process needs to be captured multiple times to provide you with a relevant sample size.
Reviewing the highest and lowest times it takes to complete a step can prompt you to ask why there might be a variance. Is this down to people, process, or something else? Different people may perform tasks differently. You can analyse further whether this is down to skill or will. Imagine how behaviour can change if the boss is watching! If there is no standard operating procedure (an agreed way of doing something, usually documented), how does this impact the variability of the process or an individual step?
Mapping a value steam provides you with a firm starting point to visualise the current state of a process and quantify the effort it is taking. Do not just reply on second hand information about what happens at each stage of the process. Go and see it. Going to see what happens is a fundamental part of Lean practice. Not only does it help you visualise the activity and validate what you’re being told, but you’ll notice so much more when you really start looking.