This reminds me that not everyone knows what I know.
If you work with distributed systems, by which I mean any system that must pass information between multiple, tightly integrated subsystems, there is a well understood concept of maximum sustainable load and we know that number to be roughly 60% of maximum possible load for all systems.
I don't have a link handy to show you the math, but the basic idea is that the probability that one subsystem will have to wait on another increases exponentially with the total load on the system and the load level that maximizes throughput (total amount of work done by the system over some period of time) comes in just above 60%. If you do less work you are wasting capacity (in terms of throughput); if you do more work you will gum up the works and waste time waiting even if all the subsystems are always busy.
We normally deal with this in engineering contexts, but as is so often the case this property will hold for basically anything that looks sufficiently like a distributed system. Thus the "operate at 60% capacity" rule of thumb will maximize throughput in lots of scenarios: assembly lines, service-oriented architecture software,
This comment is still real good. Some thoughts I've been reflecting on re: 60% rule:
I've roughly been living my life at 60% for the past year (after a few years of doing a lot of over-extension and burnout). It has... been generally good.
I do notice that, say, at the last NYC Winter Solstice, I was operating at like 105% capacity. And the result was a more polished, better thing than would have existed if I'd been operating at 60%. Locally, you do get more results if you burn your reserves, esp if you are working on something with a small number of moving parts. This is why it's so easy to fall into the trap.
But, like, you can't just burn your reserves all the time. It just doesn't work.
And if you're building a thing that is bigger than you and requires a bunch of people coordinating at once, I think it's especially important to keep yourself _and_ your allies working at 60%. This is what maximizes the awesomeness-under-the-curve.
The main worry I have about my current paradigm, where I think I'm lacking: Most of my 60%-worth of effort I spend these days doesn't really go into _improvement_ of my overall capacity, or in especially building new skills. A year-ish ago, when I dialed back my output to something sustainable, I think I cut into my self-improvement focus. (Before moving to Berkeley, I HAD focused efforts on raising the capacity of people around me, which had a similar effect, but I don't think I've done that _much_ since moving here)
My good action of the day is to have fallen in the rabbit hole of discovering the justification behind your comment.
First, it's more queueing theory than distributed systems theory (slightly pedantic, but I'm more used to the latter, which explained my lack of knowledge of this result).
Second, even if you look through Queueing theory resources, it's not that obvious where to look. I've finally found a helpful blog post which basically explains how under basic models of queues the average latency behaves like , which leads to the following graph (utilization is used instead of load, but AFAIK these are the same things):
This post and a bunch of other places mentions 80% rather than 60%, but that's not that important for the point IMO.
One thing I wonder is how this result changes with more complex queuing models, but I don't have the time to look into it. Maybe this pdf (which also includes the maths for the mentioned derivation) has the answer.
This sounds very interesting. I'm curious if anyone has a reference for the 60% number? (a few simple google searches for "maximum sustainable load distributed system" and variants didn't turn up anything)
This was a brand-new concept to me, and I suspect it's going to immediately be useful to me. Thank you very much for taking the time to explain clearly.
I find it interesting that some of the things that give slack also take it away. The obvious example is cell phones. Especially at first they gave slack by letting you leave the house while you were waiting for an important phone call, but eventually ate it by creating an expectation that you'd always be available.
I think what we are looking at here is Moloch eating all slack out of the system. I think that is a summary of about 75% of what Moloch does.
I clicked +1, but in way of feedback I would suggest trying to be more precise with your definitions. "The absence of binding constraints on behavior" sounds just like a synonym for freedom. If that was the concept that this article identified, it would be kind of pointless, but you've actually identified a new and useful concept.
This has a few advantages:
Firstly, it makes the article easier to understand. Someone people learn better by example, others better by explicit definition.
Secondly, it helps you make sure that what you have identified is indeed a single concept and not a few closely related ideas rolled into one.
Third, it allows you clarify the concept in your own head and pick more central examples to illustrate it.
Fourth, it helps set social norms by encouraging other people to carefully define their terms.
I would make an alternative definition as follows:
Firstly, we start off by assuming some kind of resource (ie. time, energy, money, social capital)
Now we can define Slack as keeping some of a resource spare so that you can spend it when opportunities come up (ie. to do things ethically/properly/just for fun/for personal growth, ect).
This is a more specif
Thank you. I agree that the definition isn't perfect and can likely be improved. "Freedom provided by having spare resources" isn't a bad second attempt but I sense we can do better; I will continue to think about the best way to pin this down concisely. Suggestions welcome!
I assert that this is also about Slack, but possibly a different kind of Slack:
https://frustrateddemiurge.tumblr.com/post/144927712238/affordance-widths
The thing is, Zvi's post here is about *not losing your affordance width*; it says nothing about how to increase it. Such a post would be highly appreciated.
I think this is a valuable concept to have, but despite thinking about it on and off ever since this was first posted (and reading the Book of the Subgenius) I still don't really understand it well enough to act on it.
I found this post immediately valuable. i appreciated your conciseness. These ideas are simple but not obvious; spending too many words explaining a simple thing makes it seem complicated.
I don't feel that Maya Millennial describes me or anybody I know. People may be in thrall to various different traps of the superego, but by no means is the only common manifestation "social media astroturfing, FOMO, 'premium mediocre something something', thinly veiled middle class trap anxiety". A rich guy becomes slave to his airplane refu
Reminds me of Meditations on Moloch. "Slack" is anything that you have/want/enjoy that you would not need/want/care about if you were optimized for competition. Which is to say, Slack is any resource you could sacrifice to Moloch for an advantage.
Thanks for sharing. I've been thinking about this sort of thing a lot the past few years, and it's nice to have a concept handle that broadly encompasses buffer money/free time/focused attention/etc, instead of referring to each individually.
Maya has adopted the goal of Appearing-to-Achieve and competition in that race burns slack as a kind of currency. She's going all-in in an attempt to purchase a shot at Actually-Achieving. Many of us might read this and consider ourselves exempt from that outcome. We have either achieved a hard goal or are playing on hard mode to get there. Be wary.
The risk for the hard mode achiever is that they unknowingly transform Lesser Goals into Greater. The slackful hobby becomes a consuming passion or a competitive attractor and then sets into a binding const
On management you write
Slack in project management is the time a task can be delayed without causing a delay to either subsequent tasks or project completion time. The amount of time before a constraint binds.
I think this is a nice short reference, but a lot lurks behind, because slack in project or process management has a long history and a lot of theory behind it. I think slack in this context can be equated with buffer capacity, at least mostly. Buffers can be good or bad. Toyota saw buffers as bad and invented Just in Time to deal with the consequence
The opposite of slack would be... deliberate constraints? Which I find very valuable. In addition to the value of deliberate constraints- Parkinson's law is a real thing, as are search costs, analysis paralysis, eustress (distress's motivating cousin). I find when I'm structured and extremely busy, I'm productive and happy, but when I have slack, I'm not.
Could this be a case of Reversing the advice you get?
Related (I think): if you're early in your career, use some of the government-mandated slack (aka weekends) to differentiate yourself and build up human capital. If you're "a programmer" and are perceived as a generic resource, the system will often drive you to compete on few visible dimensions - like hours. If you have unique and scarce skills you have bargaining power to have more Slack and your employer might even pay for you to gain more human capital. (I still continue to reinvest part of my slack time into my career, though I a)
Slack: Getting Past Burnout, Busywork, and the Myth of Total Efficiency by Tom DeMarco
Another book: Slack (unallocated time) is essential for change, learning, and even doing things well.
I'm pretty sure this is the book with the description of what happens when two companies that don't do the work to write good contracts attempt to deal with each other.
Our latest font changes made this post a bit harder to read, so I cleaned it up and converted it to our editor.
For some reason I remembered "In praise of Idleness" by Bertrand Russell. Seems relevant, although not entirely the same. Some choice quotes.
Another disadvantage is that in universities studies are organized, and the man who thinks of some original line of research is likely to be discouraged. Academic institutions, therefore, useful as they are, are not adequate guardians of the interests of civilization in a world where everyone outside their walls is too busy for unutilitarian pursuits.
In a world where no one is compelled to work more than f
I think a nice, short definition of Slack would be, "A small gradient of the cost function in the vicinity of the optimum." In other words, the penalty for making sub-optimal decisions is not very high, because the region of acceptable behaviors around the best one is fairly large.
And yet here we are, where the penalties for sub-optimal decisions are indeed quite high. The obvious question is, "How did it get to be this way?" Well, typically non-smooth cost functions indicate more complexity, so in some sense the decision landscape has
My model of this problem is that firms cannot pay the hyper-talented what they are worth because the other employees would not stand for it. We have constructed norms whereby hyper-productive CEOs and other executives can get pay that is many times that of their employees, and still this causes massive resentment and even calls for government intervention. If programmers that were 100x as valuable as the average got even 10x the pay, the other employees would strike or riot. Equity does seem to be one way around this trap in some circumstances.
I have personal experience with this. I got [company I used to work for] to hire a very good programmer for a contract, he got the job done ahead of schedule and made us tons of money, and we couldn't renew for another project, because other programmers found out what he was paid and threatened to quit. So he took a higher-paying job elsewhere.
This reminds me of reading Walden. Thoreau's lifestyle during that period feels like the opposite of the description of Maya's position here.
Re ‘Slack is life’, cf the phrase ‘work-life balance’, where life implicitly means non-working time, i.e. (roughly speaking) slack.
(PS heading ‘The Slackless Like of Maya Millennial’ presumably should read ‘The Slackless Life…)
My guess is that 'Slack' reads differently in social and material reality. Maya is, in a sense, signaling infinite slack, but in a manner which actually consumes any possible reserve of slack. I think a careful reading of Rao shows that sacrificing the thing for the representation of the thing is what he refers to as 'creating social capital'.
Just a data point: I've yet to find a Zvi post enjoyable to actually read. When I make myself slog through them, there's always valuable and interesting concepts, and I'm usually better off for having put forth the effort, and so I upvote and am grateful to Zvi for sharing. But at the same time, the experience is one of trying to make sense of postmodernist slam poetry, or having to consciously sort out which words are jargon and which words are filler and which words just mean what they say, or trying to parse the statements of someone on a half-dose of mushrooms. It always feels like things could've been 50% more straightforward while still being aesthetically unique and interesting. It sort of feels like the writing doesn't try to optimize for limited working memory, maybe?
(All of this really truly just meant for data/feedback; I have no desire to communicate any sort of a demand-for-change and don't claim that it's "wrong" in any way except for me personally. It's just that, in Zvi's shoes, I would want to know if I were imposing a cost on some readers. Doesn't mean I wouldn't continue to impose it, if that were the right move.)
Thank you for saying it. Feedback of this type is hard to get and quite valuable, especially given you grok the posts after doing the work. The concept that I might not be accounting for limited working memory is especially new and interesting. I've been making an effort to make the jargon/non-jargon distinction clear, but it's a known issue and I don't love my solutions so far. There's tension with brevity; I'm trying hard to keep things short.
I don't think you're the only person who has this issue, so I need to fix it. Tsuyoku Naritai. If you're willing I'd love to hear more (here or elsewhere), the more detailed and concrete the better.
Epistemic Status: Reference post. Strong beliefs strongly held after much thought, but hard to explain well. Intentionally abstract.
Disambiguation: This does not refer to any physical good, app or piece of software.
Further Research (book, recommended but not at all required, take seriously but not literally): The Book of the Subgenius
Related (from sam[ ]zdat, recommended but not required, take seriously and also literally, entire very long series also recommended): The Uruk Machine
Further Reading (book): Scarcity: Why Having Too Little Means So Much
Previously here (not required): Play in Hard Mode, Play in Easy Mode, Out to Get You
Leads to (I’ve been scooped! Somewhat…): Sabbath Hard and Go Home
An illustrative little game: Carpe Diem: The Problem of Scarcity and Abundance
Slack is hard to precisely define, but I think this comes close:
Definition: Slack. The absence of binding constraints on behavior.
Poor is the person without Slack. Lack of Slack compounds and traps.
Slack means margin for error. You can relax.
Slack allows pursuing opportunities. You can explore. You can trade.
Slack prevents desperation. You can avoid bad trades and wait for better spots. You can be efficient.
Slack permits planning for the long term. You can invest.
Slack enables doing things for your own amusement. You can play games. You can have fun.
Slack enables doing the right thing. Stand by your friends. Reward the worthy. Punish the wicked. You can have a code.
Slack presents things as they are without concern for how things look or what others think. You can be honest.
You can do some of these things, and choose not to do others. Because you don’t have to.
Only with slack can one be a righteous dude.
Slack is life.
Related Slackness
Slack in project management is the time a task can be delayed without causing a delay to either subsequent tasks or project completion time. The amount of time before a constraint binds.
Slack the app was likely named in reference to a promise of Slack in the project sense.
Slacks as trousers are pants that are actual pants, but do not bind or constrain.
Slackness refers to vulgarity in West Indian culture, behavior and music. It also refers to a subgenre of dancehall music with straightforward sexual lyrics. Again, slackness refers to the absence of a binding constraint. In this case, common decency or politeness.
A slacker is one who has a lazy work ethic or otherwise does not exert maximum effort. They slack off. They refuse to be bound by what others view as hard constraints.
Out to Get You and the Attack on Slack
Many things in this world are Out to Get You. Often they are Out to Get You for a lot, usually but not always your time, attention and money.
If you Get Got for compact amounts too often, it will add up and the constraints will bind.
If you Get Got even once for a non-compact amount, the cost expands until the you have no Slack left. The constraints bind you.
You might spend every spare minute and/or dollar on politics, advocacy or charity. You might think of every dollar as a fraction of a third-world life saved. Racing to find a cure for your daughter’s cancer, you already work around the clock. You could have an all-consuming job or be a soldier marching off to war. It could be a quest for revenge, for glory, for love. Or you might spend every spare minute mindlessly checking Facebook or obsessed with your fantasy football league.
You cannot relax. Your life is not your own.
It might even be the right choice! Especially for brief periods. When about to be run over by a truck or evicted from your house, Slack is a luxury you cannot afford. Extraordinary times call for extraordinary effort.
Most times are ordinary. Make an ordinary effort.
You Can Afford It
No, you can’t. This is the most famous attack on Slack. Few words make me angrier.
The person who says “You Can Afford It” is saying to ignore constraints that do not bind you. If you do, all constraints soon bind you.
Those who do not value Slack soon lose it. Slack matters. Fight to keep yours!
Ask not whether you can afford it. Ask if it is Worth It.
Unless you can’t afford it. Affordability is invaluable negative selection. Never positive selection.
The You Can Afford It tax on Slack quickly approaches 100% if unchecked.
If those with extra resources are asked to share the whole surplus, all are poor or hide their wealth. Wealth is a burden and makes you a target. Those visibly flush rush to spend their bounty.
Where those with free time are given extra work, all are busy or look busy. Those with copious free time seek out relatively painless time sinks they can point to.
When looking happy means you deal with everything unpleasant, no one looks happy for long.
The Slackless Like of Maya Millennial
Things are bad enough when those with Slack are expected to sacrifice for others. Things are much worse when the presence of Slack is viewed as a defection.
An example of this effect is Maya Millennial (of The Premium Mediocre Life of Maya Millennial). She has no Slack.
Constraints bind her every action. Her job in life is putting up a front of the person she wants to show people that she wants to be. If her constraints noticeably failed to bind the illusion would fail.
Every action is being watched. If no one is around to watch her, the job falls to her. She must post all to Facebook, to Snapchat, to Instagram. Each action and choice signals who she is and her loyalty to the system. Not doing that this time could mean missing her one chance to make it big.
Maya never has free time. There is signaling to do! At a minimum, she must spend such time on alert and on her phone lest she miss something.
Maya never has spare cash. All must be spent to advance and fit her profile.
Maya lacks free speech, free association, free taste and free thought. All must serve.
Maya is in a world where she must signal she has no Slack. Slack means insufficient dedication and loyalty. Slack cannot be trusted. Slack now means slack later, which means failure. Future failure means no opportunity.
This is more common than one might think.
“Give Me Slack or Kill Me” – J.R. “Bob” Dobbs
The aim of this post was to introduce Slack and give an intuitive picture of its importance.
The short-term practical takeaways are:
Make sure that under normal conditions you have Slack. Value it. Guard it. Spend it only when Worth It. If you lose it, fight to get it back. This provides motivation for fighting things Out To Get You, lest you let them eat your Slack.
Make sure to run a diagnostic test every so often to make sure you’re not running dangerously low, and to engineer your situation to force yourself to have Slack. I recommend Sabbath Hard and Go Home with my take to follow soon.
Also respect the Slack of others. Help them value and guard it. Do not spend it lightly.
A Final Note
I kept this short rather than add detailed justifications. Hopefully the logic is intuitive and builds on what came before. I hope to expand on the details and models later. For a very good book-length explanation of why lacking Slack is awful, see Scarcity: Why Having Too Little Means So Much.