Quite often, when exploring the anatomy of the Cumulative Flow Diagram with agile teams I work with, one of the challenges that pops up is understanding the arrival and throughput rates. Why do we need to track these, and why do they matter?

Today, I’ll walk you through the basics of this concept and show you how to use it to optimize your workflow.

Without further ado, let’s get started.

What Are Arrival and Throughput Rates and How Are They Calculated?

Simply put, the arrival rate is the rate at which tickets enter your workflow. It shows how quickly you start new work. Your arrival rate is represented by the top line on a Cumulative Flow Diagram.

Track the Number of Tasks With Nave | Image

The arrival rate is calculated by tracking the number of tasks that enter the workflow over a specific period.

For example, if you track the total number of tasks that arrived each day and add them up, you get the total number of tasks for that period.

You then divide that number by the number of days in the selected period. For the period between May 15, 2023, and May 15, 2024, which is 363 days, 87 tasks arrived. So, the arrival rate is 87/363 = 0.24 tickets per day.

The throughput rate in a Cumulative Flow Diagram refers to the amount of work your team delivers over a certain period. In the diagram, this is represented by the slope of the Done line.

Slope Of The Done Line in Nave | Image

To calculate the throughput rate, you look at the slope of the Done line between any two points. For example, for the period between May 15, 2023, and May 15, 2024, which is 363 days, the team delivered 87 tickets. Therefore, the throughput rate is 87/363 = 0.24 tickets per day.

What Do Arrival and Departure Rates Tell Us and Why Does It Matter?

Okay, now, let’s break this down to see why this information matters and how we can use it to balance demand and capacity.

Monitoring the arrival rate is important because if work enters the system faster than it leaves, you are accumulating work in progress.

Think of work in progress as a liability. You want less of it. Your liability becomes an asset only when your work is delivered to your customers.

Your goal should be to keep as much work in progress as your team can handle at any one time and focus on finishing work rather than starting new work.

Furthermore, your throughput rate represents your team’s capacity to deliver results. Ideally, the steeper the slope of your Done line, the higher the throughput rate, meaning your team is completing tasks quickly.

Conversely, a flatter slope indicates a lower throughput rate, meaning your team’s delivery speed slows down.

3 Tips to Balance Arrival and Departure Rates

The arrival and departure lines on the Cumulative Flow Diagram should ideally be roughly equal to maintain a predictable and stable workflow. This means that the distance between the lines should remain consistent over time.

If the arrival rate is higher than the departure rate, the distance between the lines will expand. If this is your situation, here are some steps you can take to balance demand and throughput.

#1 Monitor the Cumulative Flow Diagram

If you can’t measure it, you can’t improve it! Make it a practice to analyze your Cumulative Flow Diagram during retrospectives. Focus on how your arrival and throughput lines build over time.

As soon as you notice that these lines are not growing in parallel, either increasing or declining, take this as a trigger to take action.

Here is how to get started with the Nave’s analytics suite in less than a minute →

#2 Apply Work in Progress Limits

Applying WIP limits is a game-changer! In one fell swoop, it relieves overburden, eliminates multitasking, and prevents context switching.

Delivery times also rapidly go down, which is one of the strongest motivational boosters. What’s more, now that there is less of it at a time to handle, you’ll find that work is being done with more precision and delivered at a higher level of quality.

If you haven’t used WIP limits before, here is the 3-step guideline to implement this practice successfully

#3 Implement a Pull System

Unlike a push system, where work is pushed onto teams regardless of their capacity, pull systems prevent team overburden and increase flow efficiency.

Teams pull work as they finish what they started while keeping their focus on the highest priorities. Pull systems significantly improve productivity and decrease delivery times.

Here is how to design a pull system that enables you to keep your arrival and departure rates in check

Here is your action item: If you haven’t connected the Nave to your management platform, now is the time! It’s free for 14 days no strings attached →

Create your dashboard and explore your Cumulative Flow Diagram. What do your arrival and departure lines look like?

Connect with me on LinkedIn and send me a DM—I want to hear from you! I’d love to know what patterns you have identified and what steps you’re planning to take to enable a stable delivery system. It’s all it takes to start making reliable data-driven decisions.

Wishing you a productive day ahead! I’ll see you next week, same time and place, for more managerial insights. Bye for now!

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