Value stream map

The steps run left to right in boxes, each with the time someone actually spends on the work there: the touch time. Between the boxes are the waits: how long the work sits before the next step picks it up. A timeline along the bottom adds both up, so the map ends with two numbers, the total touch time and the total elapsed time, and the gap between them.

Full value stream maps also show the flow of information that triggers each step, and in manufacturing they carry stock levels and machine data. For most service work, the steps, the touch times and the waits are what matter, and a map with just those is worth drawing today rather than perfecting next month.

Use it when the complaint is time: a referral takes three weeks, a claim takes a month, a hire takes a quarter. It is the tool that shows where that time goes, and it almost always shows that the work itself takes hours while the waiting takes weeks.

Not for a problem of quality rather than time; a Pareto chart and a fishbone diagram will do more. Not for a process that varies so much case to case that no single path describes it; map the most common path, say so, and note the others. And not from a desk. A map drawn from the procedure manual shows the process as written; walk the work, or follow real cases through the system, and draw what happens.

Divide the total touch time by the total elapsed time. In most services that share is a few per cent at best; under one per cent is common. The biggest gains are almost always in the waits, not in making the work faster, so read the gaps between the boxes first, longest first.

Then ask of each wait: what is the work waiting for? A decision, a batch, a diary slot, a reply, a hand off between teams. Each answer is a different kind of fix.

The employment support service from the SIPOC page followed referrals from arrival to first appointment and recorded, for a typical case, the minutes of work at each step and the days the case waited before the next. The figures are illustrative.

The work adds up to 115 minutes, under two hours. The case waits 21 days. Touch time is less than half of one per cent of the time the participant waits. The longest single wait, 9 days, comes after the appointment is offered and before it happens, while the participant waits for a slot in an adviser's diary; the next longest, six days, is while the offer goes out and the service waits for a reply.

Neither of those is fixed by working faster. The obvious changes are about the waits: offering the appointment in the first phone call, with the diary open, rather than by letter; and keeping slots free for new starters each week. Both are tests to run, measured on a run chart of days from referral to first appointment.

One ratio sums up the map: how much of the time the work is actually being worked on.

Use the first and last steps from the SIPOC. Follow several real cases through, and for each step record the work time and the wait that follows, from timestamps where they exist and by asking where they do not. Draw the steps as boxes, the waits between them, and the timeline beneath. Put the two totals and the share at the end, in large type.

Draw it with the people who do the work. They will correct it, and the corrections are often the most useful part.

A first value stream map belongs to Define and Measure: it shows where the time goes and sets the baseline. A future state map, drawn with the waits removed or shortened, becomes the plan for Improve.