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Eat my theory of constraints

Recently, I volunteered to make free lunches for over 2,600 school kids. As well as doing good, I felt this could be a fantastic opportunity to observe the theory of constraints in practice. It was, and I discovered some really unexpected insights (for me). 

First some background. The theory of constraints is a business concept that describes how all processes have constraints that restrict how much they can produce, and what we can do to smooth out the flow. This is most often observed as material building up or running out.

This opportunity was courtesy of Eat My Lunch, a charity who deliver deli-style lunches to busy people, and use the proceeds to provide free lunches to school kids who don’t have access to a well-rounded lunch. An awesome idea that started 2.5 years ago delivering lunches to South Auckland schools, and has since expanded to Hamilton, Wellington, and more of Auckland. 

A worthy endeavour, and one that Fiserv (where I am currently Manager of Agile PMO and Coaching) was keen to include in its roster of charities they give staff time to support. 

The luncheon production

Let me wax lyrical for a moment to paint the scene for you. Imagine, if you will, a cold warehouse at 6am. Around 20 permanent staff are there already, getting bread and fruit out of cold storage ready for around 40 volunteers to start making and packing lunches. 

They welcomed in the volunteers with promise of coffee and breakfast (after 3 hours hard labour). The warehouse floor was divided into seven zones. I don’t know what they were called at Eat My Lunch, so I have named that for what they were doing. 

  1. Along one side was the cold storage mentioned earlier. 
  2. At the back was the premium lunch zone, where they made lunches for their paying clients. These were made exclusively by their permanent staff. Quality control at play.

The rest of the floor was given over to the main production process, making lunches for the school kids.

  1. We had a bread buttering zone. This was an amazing sight. Several whole packs of bread would be laid out slice by slice, including the end slices (crust side up — so that it still look like a sandwich when closed). A team of people buttered and re-stacked these, butter-side together. 
  2. Next we had the filling zone, where people put meat and coleslaw between the slices, cut them in half, and lined these up on trays. 
  3. Then we had the bagging and boxing zone, where the sandwiches were wrapped in greaseproof bags, put into a large brown bag with an apple and a chocolate-chip cookie, and then the brown bags were placed in boxes.
  4. This continued until there were enough in the box for a school, at which point the box was moved to the holding zone, from it would later be loaded into a van to be taken off to the schools. 
  5. Lastly, there was the control zone, where I was fortunate enough to help out. It was positioned halfway along one side, so that we had a great view across the whole floor.

My insights

Having described the process, I hope you are able to picture some of what was going on that morning. However, I mentioned at the beginning that the reason for writing this post was to share with you some insights I had.

Batch sizes

Everything flowed as much as it could, but we did have to move food between the zones and finally get it out to the schools. This means collecting it together in batches, and whenever you move things in batches it makes the flow of work more lumpy. I was, however, impressed with their approach to controlling these batch sizes.

To keep things as smooth as possible, it’s better to keep batch sizes small. Luckily, the batch size for moving food between zones was naturally limited to how much we could fit on a tray. This made it small and predictable.

The delivery for each school, however, was highly variable as it was dependant on the number of children needing a free lunch. While it was variable, though, it was predictable and controlled by the early staff preparing the boxes. Each box was labelled with the name of the school and the number of lunches required. Essentially like the original kanban card. As the boxes were brought through for us, they already contained the right number of brown paper bags. Some batches were smaller and some were larger, but this was already defined for us. As we pulled the next box, we didn’t need to count bags, we just had to stuff them, and keep it flowing.

Generalising specialists

The real challenge in any process like this is to get the pace right at each zone so that we never had too much building up next to someone and nobody ever ran out and sat idle. This much we know from the theory of constraints; however, the real light-bulb over the head moment (for me) was seeing how Eat My Lunch dealt with this. The more astute of you will already be there, I know, but bear with me.

The control zone, where I was working, showed itself to be critical in three ways:

  • Firstly, they would ensure that raw materials were coming out to the zones in time, that the tables and floor were kept clean of bits of food, and that rubbish was taken away.
  • Secondly, if they saw too much building up in a zone, they would take some away to process in our zone.
  • Lastly, and more importantly, if they saw the supply starting to run out anywhere, they would step in and lend an additional pair of hands to help build the flow up again, then step back out. They also stepped in when anyone needed to take a break, ensuring the flow was not broken. 

It is this generalising specialist role that intrigued me. Without the experienced people who did this, we would still have had food building up or running out throughout the morning. Maybe this is obvious to some, but I had not read about how critical this role could be in ensuring flow. Perhaps it was only required here because nobody was familiar with the process.

Either way, experiencing this in such a physical way has made it more significant to me. This will be an experience that stays with me for a long time.

I am now giving thought to how these insights could be applied to knowledge work, both to help how we coach teams at Fiserv as well as how it can inform my training workshops. 

I would be keen to hear from others on similar experiences.  

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