Why limiting work-in-progress works
lethain.com
Why limiting work-in-progress works
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Re: Why limiting work-in-progress works
#2So having read the article, why does limiting work-in-progress work? Because it allows you to finish more work that you start? I struggled a little bit initially with the generic concepts used for modeling. But I suppose the real insight is that, focusing only on these 3 basic parameters (work started, work finished, and number of developers), you can get wildly different results. Is that a fair reading?
This is a topic to which I've given a fair deal of attention in leading software development teams using scrum. Especially after reading Donald Reinertsen's Principles of Product Development Flow, where he approaches this topic in more depth:
https://www.goodreads.com/book/show/22586058-the-principles-...
Limiting work-in-progress was a major principle in Reinertsen's book. Another related one which I've applied successfully in practice: limit batch size. In my case using scrum, this meant keeping user stories within a certain size range (2-5 points).
This has an important benefit: it controls scope creep. It does this a couple ways: 1. It's helps during planning avoid overlooking complications or other costly delays before works gets started. 2. When a story starts to creep during development, you tend to catch it sooner and control it more effectively.
Which helps get stuff done, which helps limit WIP, which as the article suggests helps get stuff done.
Re: Why limiting work-in-progress works
#3So having read the article, why does limiting work-in-progress work? Because it allows you to finish more work that you start? I struggled a little bit initially with the generic concepts used for modeling. But I suppose the real insight is that, focusing only on these 3 basic parameters (work started, work finished, and number of developers), you can get wildly different results. Is that a fair reading? This is a to…
Limiting in progress is similar to thread pooling, which gives u graceful degradation.
Re: Why limiting work-in-progress works
#4Two of the most under-appreciated insights in software engineering: concurrent work in progress has a productivity cost, and team size has a productivity cost (The Mythical Man Month).
If you ever want to see cognitive dissonance in action, try talking about this with engineering managers at a hypergrowth company. They will smile and nod and agree and go right back to pushing for ever increasing scope + headcount and and acting surprised when they don’t get linear-plus returns. There’s a really persistent belief that you can just grow the team faster than the backlog and everything will be fine.
Re: Why limiting work-in-progress works
#5So having read the article, why does limiting work-in-progress work? Because it allows you to finish more work that you start? I struggled a little bit initially with the generic concepts used for modeling. But I suppose the real insight is that, focusing only on these 3 basic parameters (work started, work finished, and number of developers), you can get wildly different results. Is that a fair reading? This is a to…
> So having read the article, why does limiting work-in-progress work?
I imagine his models are those code blocks just above the images.
A reference to the language those are written on would be great, and would let we check if the code is really realistic. But it's lacking, so I can't explain why the article claims this.
Limiting WIP happens to work on practice, and is the basis of the kanban process (both the one we use in software development, that doesn't even have a kanban, and the industrial one). Scrum does give you some tools you can repurpose into managing WIP, but those are not as robust.
Re: Why limiting work-in-progress works
#6Two of the most under-appreciated insights in software engineering: concurrent work in progress has a productivity cost, and team size has a productivity cost (The Mythical Man Month). If you ever want to see cognitive dissonance in action, try talking about this with engineering managers at a hypergrowth company. They will smile and nod and agree and go right back to pushing for ever increasing scope + headcount and…
I have seen this change when I was working at Google. The key problem was that the PM to Engineer ratio increased in the company, and we were getting a lot of extra work from the PMs that looked nice on paper, were easy to understand, but didn't have a real positive impact on the customer. This extra work completely blocked us from improving the performance of the product.
Re: Why limiting work-in-progress works
#7Slow CI and/or Code Review makes concurrent work a bit of a necessity. Context switching certainly has a cost, but it's cheaper for my employer than paying me to wait for tests to run.
Re: Why limiting work-in-progress works
#8Im unconvinced. Making sciency charts doesnt mean there's well grounded research.
The only place i worked that had a WIP limit... i never got the point. Like agile seems to be largely about visibility for management or clients, so the idea of artificially restricting people from reporting what theyre doing... like why?
Re: Why limiting work-in-progress works
#9Im unconvinced. Making sciency charts doesnt mean there's well grounded research. The only place i worked that had a WIP limit... i never got the point. Like agile seems to be largely about visibility for management or clients, so the idea of artificially restricting people from reporting what theyre doing... like why?
By the way here's what actually happens when you set in place WIP limits. I think most of us adult professionals realize that a person has a few things on their plate and a thing can be "in progress", but waiting on something, and they probably don't have the patience to move it around on your JIRA board every couple hours. So your task management essentially becomes a narrative. So you get people to lie to you and pretend like they're super focused on this one priority. It's a ridiculous game. Just don't play it.
Re: Why limiting work-in-progress works
#10Slow CI and/or Code Review makes concurrent work a bit of a necessity. Context switching certainly has a cost, but it's cheaper for my employer than paying me to wait for tests to run.
Actually...
I've had this exact problem (~30min CI and slow CR) on my current project. For a while I've sucked it up and did concurrent work as you say.
After a while it becomes apparent that this concurrent work is making us lose a lot of time:
- PRs still aren't merged several days (2 on average, regularly more) after being open. The longer they stay the more expensive they become (regular rebasing, context-switching, CRs being more and more exigeant and enlarging the scope of the PR) - Bugs appear. Doing several things in parallel leads to a loss of quality. - We're not improving, this unideal situation becomes the norm.
So I'm trying something else: we're not starting a new ticket before the last one is done. That means waiting for CR, waiting for the CI. That means having times where my employer pays me to wait for tests to run. Well, the result:
- We're actually faster. The context switching + rebasing cost is far higher than waiting 30min for tests to pass. - Now, the problem that the CI and the CRs are slow is visible (I'm visibly not doing anything), which means that we can work on it and improve! That's a basis of lean manufacturing: make problems visible. - We chase people to get reviews, so the lead time of each ticket significantly decrease. Also I'm automatically available to help people review my code (if it's a complex bit or it's a junior reviewing). - We take tickets to improve our CI and our testing perfs
All in all, doing one thing at a time was already more efficient, and in addition we can make our process more and more efficient.
The main pushback on this is generally "but we need to context-switch to review PRs", but in the end you do way more context switching when working on several things at once.