Sunday, September 30, 2012

Playing with Little‘s Law


Little’s Law, as we use it in Kanban, states a relationship between average Lead Time, average Throughput and average Work in Progress.
The original formula comes from queuing theory and looks like this:  

L = λ x W

L is the average number of items in a queuing system.
λ is the average number of items arriving into the queuing system over some unit of time
W is the average time a work item spends overall in the queuing system

If we transfer the formula into knowledge work, there are some interesting implications we have to consider. For example: Did you know that Little’s Law only holds true in a stable system where we have Conservation of Flow? This means that every work unit passes the whole system and that the average arrival rate of work equals the average departure rate. I strongly recommend Frank Vega’s great Blog Post Little’s Law: Isn’t ita Linear Relationship? on this topic! My main takeway from Frank’s article is that we need to dig a little bit deeper into the topic before we start calculating lead times according to Little’s Law.

But besides this calculations (at the Advanced Kanban Metrics Tutorial in Boston we called this „The Fancy Stuff“), there are some other interesting things we can use Little’s Law for. For example: discussion!
Here are some examples of fruitful discussions I had with different teams over the last couple of months. This is the variant of Little’s Law which I use (and which is probably most common within the Kanban community):



The first interesting thing here is: If we want to shorten Lead Times (and who does not want to do this?), we have two choices: We can either increase Throughput or decrease the Work in Progress (WIP). This ist trivial, right? But as soon as we make people think about the measures they typically take to shorten lead times, we will probably discover something interesting: Most of them are on the Throughput side. Hiring additional staff, making people work overtime, buying better tools, building frameworks, yelling at people...All these means are quite common in our industry – and they all try to increase the Throughput. But do they work well? In most cases: No! There are different reasons behind this. One is Brooke’s Law. Another one might be that most of these measures lead to a deep J-Curve, meaning it gets much worse before it gets better. So instead of trying harder and harder to increase Throughput, perhaps we should have a look at the numerator of the equation: Work in Progress. If we manage to decrease the WIP, this would lead to shorter lead times. The simpliest way for doing so is to establish a new policy that states: „We as a team agree that we do not want to have more than X items in progress at any time. Before we start another item, we need to finish an old one first.“
Perhaps it is as simple as this. Perhaps it isn’t. But the interesting point here is that now the teams starts discussing things in a completely different way, because they’ve never thought about it from this perspective!

Now let’s go one step further. So far we’ve assumed that we take a measure (new tool, new policy etc.) and this measure will only effect one part of Little’s Law (e.g. Throughput). In practice it’s often not that simple. Let’s take Pair Programming as an example. What will happen if a team starts pairing? One effect might be that the Throughput goes down, because utilization of team members goes down. And this is certainly the most common argument against Pair Programming. (Let’s forget the fact for know that in reality often Throughput does not go down, because pairing leads to less multitasking and better focus.) At the same time something else happens: Pair Programming means that we decrease WIP dramatically! And this will lead to shorter Lead Times. So what we observe in reality quite often is that the overall Lead Time after introducing Pair Programming will be shorter than before – in addition to higher quality and better risk management through continuous knowledge transfer. We’ve seen this happening many times. But it sounds counter intuitive and therefore it’s hard to convince people to give it a try. Using Little’s Law as a model can help making these effects clearer and easier to understand/explain.
Let’s look at another example: utilization. If we consider our Lead Times to be too long, our first reaction is: We need to work more efficiently. And we get there by higher utilization. So we start „managing people“ better so that they don’t have any idle times anymore. According to Little’s Law this might be a good thing to do in order to increase Throughput. But what we often forget is the fact that at the same time we increase the WIP. How can we get better utilization of people? We make them work at new tasks every time they have spare capacity! So the overall effect of higher utilization is often longer Lead Times instead of shorter ones (not to mention poorer quality and a higher stress level of the employees)!

I would be interested in your experiences: How do you use Little’s Law? Do you find it useful? Do you have other examples for fruitful discussions? Please leave a comment!

P.S. If you want to learn more about the fancy side of Little’s Law, you really should attend Lean Kanban Central Europe in Vienna, Oct 22-23. Dan Vacanti will give his talk Little’s Flaw, and together with Frank Vega, he will give the workshop Advanced Kanban Metrics which I really recommend!




86 comments:

  1. Hello,

    My name is Andrea Ross. I live in Richmond Virginia, USA and am the lead for a Kanban User Group. I also work at the Virginia Dept of Corrections.

    I've been asked to do a presentation on Kanban for the Lean Government conference in Maryland in October. I love the slide of Jason and Little's Law and am hoping you would not mind if I use it in my presentation. I would be happy to give you credit for it in the presentation.

    You can reach me at AndreaDeniseRoss@Gmail.

    Thanks for considering my request!

    Andrea

    ReplyDelete
  2. ne of the essential contrasts between man-made-laws and the laws of Nature is that the laws of nature are unconstrained as they require no exertion in usage. Recover My Wages

    ReplyDelete
  3. Thanks for the great tips for hiring a good divorce lawyer. My friend will need these tips because she’s looking at getting a divorce pretty soon. I’ll make sure that she knows those three websites you mentioned where she can look for recommendations. She’ll need professional help, so this is great.iot development kit

    ReplyDelete
  4. A restorative gadget is intended to spare and ensure your life not hurt it. What you should do is connect with an accomplished attorney and they will choose whether or not the gadget is genuinely to blame.slip and fall attorneys

    ReplyDelete
  5.  A portable fish finder is a good choice if you don't fish from the same ship all the time. James Bach

    ReplyDelete
  6. Nice post! This is a very nice blog that I will definitively come back to more times this year! Thanks for informative post. Bail Bondsman

    ReplyDelete
  7. Thanks for the great tips for hiring a good divorce lawyer. My friend will need these tips because she’s looking at getting a divorce pretty soon. I’ll make sure that she knows those three websites you mentioned where she can look for recommendations. She’ll need professional help, so this is great.Best Accident Attorney

    ReplyDelete
  8. Hi Emma. week 2 exercise was very nice challenge. i didn't manage to remove (All) from my title and from my slicer though. inheritance law

    ReplyDelete
  9. Indeed, even the words like charming and intriguing can't do full equity with regards to depicting this blog.
    Los Angeles accident lawyers

    ReplyDelete
  10. Here are 7 health benefits based on the science of manuka honey.
    Honey offers antibacterial and antioxidant properties

    ReplyDelete
  11. Good Exercise Emma! I used LOD instead of windows sum and index. This tells how important is to know the order of operations in tableau.avocat succession paris

    ReplyDelete
  12. Thanks for taking the time to discuss that, I feel strongly about this and so really like getting to know more on this kind of field. Do you mind updating your blog post with additional insight? It should be really useful for all of us. san francisco labor attorney

    ReplyDelete
  13. Great job here on _______ I read a lot of blog posts, but I never heard a topic like this. I Love this topic you made about the blogger's bucket list. Very resourceful. employment attorney san diego

    ReplyDelete
  14. Inspiring and very useful, highly recommended for all bloggers out there.
    Yeargan & Kert, LLC - Atlanta, GA

    ReplyDelete
  15. This is very educational content and written well for a change. It's nice to see that some people still understand how to write a quality post.! work retaliation lawyers

    ReplyDelete
  16. Very nice article, I enjoyed reading your post, very nice share, I want to twit this to my followers. Thanks!. buy 50 instagram likes instantly

    ReplyDelete
  17. I have express a few of the articles on your website now, and I really like your style of blogging. I added it to my favorite’s blog site list and will be checking back soon… Application for Unlawful Termination

    ReplyDelete
  18. If you're in Los Angeles, and need a divorce lawyer, consider speaking to Spodek Law Group! They're a top rated Los Angeles divorce law firm.

    ReplyDelete
  19. A restorative gadget is intended to spare and ensure your life not hurt it. What you should do is connect with an accomplished attorney and they will choose whether or not the gadget is genuinely to blam.Botox claim

    ReplyDelete
  20. These things are very important, good think so - I think so too... paulmankin.com

    ReplyDelete
  21. What I see as what will cause the interesting scenes in Family Law #3 is the interaction of different species that hardly know each other different reactions to what they run into during the fleet return via a different route.dental negligence

    ReplyDelete
  22. Having said that, don't just go for the tough classes; it would be a serious blunder to choose a course outside of your interest just because it is hard and you believe it to give you advantage in your law school application. https://dr-goz-peter-ugyved.business.site/

    ReplyDelete
  23. Positive site, where did u come up with the information on this posting? I'm pleased I discovered it though, ill be checking back soon to find out what additional posts you include. Assault On A Public Official

    ReplyDelete
  24. The EC law just as the customary English law might just have their own legitimizations and explanations behind after a specific framework; yet it is presented that this is by all accounts not just a matter of distinction in way of approach or mentality yet additionally a matter of prioritization of the targets by both the EC law and conventional English law on locale. The rundown of cases referenced hereinafter to serve explaining the theme being talked about are, as will be obvious, settled under the Brussels Convention which can be utilized for deciphering the standards under the Regulation. Visit us

    ReplyDelete
  25. I’ve been searching for some decent stuff on the subject and haven't had any luck up until this point, You just got a new biggest fan!..sugar daddy

    ReplyDelete
  26. Yes i am totally agreed with this article and i just want say that this article is very nice and very informative article.I will make sure to be reading your blog more. You made a good point but I can't help but wonder, what about the other side? !!!!!!THANKS!!!!!! กาแฟออแกนิค

    ReplyDelete
  27. In a regular separation including a youngster, perpetual actual authority is granted to the parent with whom the kid w ill live, while the other parent is considered a "custodial parent.David Iancu

    ReplyDelete
  28. I like the idea that hiring an experienced car accident lawyer can help you bargain for a higher settlement due to his experience on what amount best suits to the type of situation you’re facing. This makes perfect sense since most of them have years of experience defending other clients in the field and have likely encountered the same scenario you have. I don’t need one at the moment but this is something to keep in mind and be prepared for in the event that unfortunate things take place.slavaguide.com
    slavaguide.com
    slavaguide.com
    slavaguide.com
    slavaguide.com

    ReplyDelete
  29. Hi there! Nice material, do keep me posted when you post something like this again! I will visit this blog leaps and bounds for more quality posts like it. Thanks... 파워볼사이트

    ReplyDelete
  30. This was really an interesting topic and I kinda agree with what you have mentioned here! 현금바둑이

    ReplyDelete
  31. Great post but I was wondering if you could write a little more on this subject? I’d be very thankful if you could elaborate a little bit further. Thanks in advance! 먹튀폴리스

    ReplyDelete
  32. Es ist eine großartige Website.. Das Design sieht sehr gut aus.. Weiter so!. hyazinthen vermehren

    ReplyDelete
  33. bagus banget, terimakasih infonya semoga bermanfaat. https://squabumin.com/madu-nafsu-makan-anak-sehat-yang-terbaik/

    ReplyDelete
  34. Experience is one thing, but relevant experience is another, like you say. If I ever am in need of a criminal lawyer, I am going to want to have one that knows exactly what I am being prosecuted for, in addition to knowing all of the legalese. You are so right when you say that having a good lawyer puts you in a better position, regardless of what happened.timeshare nonjudicial forclosure

    ReplyDelete
  35. It is very good, but look at the information at this address. adwokat wrocław

    ReplyDelete
  36. But the filmed motion picture producers to worry about, are the ones who act as if they are entertainment lawyers - but without a license or entertainment attorney legal experience to back it up. Filmmaking and motion picture practice comprise an industry wherein these days, unfortunately, "bluff" and "bluster" sometimes serve as substitutes for actual knowledge and experience. But "bluffed" documents and motion picture production procedures will never escape the trained eye of entertainment attorneys working for the studios, the distributors, the banks, or the errors-and-omissions (E&O) insurance carriers. For this reason alone, I suppose, the job function of film production counsel and entertainment lawyer is still secure. toxic baby formula products

    ReplyDelete
  37. Netter Post. Ich habe diesen Blog ständig überprüft und bin beeindruckt! Äußerst hilfreiche Informationen, besonders der letzte Teil, ich interessiere mich sehr für solche Informationen. Ich habe sehr lange nach genau diesen Informationen gesucht. Danke und viel Glück. Saunen und Bäder in Ihrer Nähe

    ReplyDelete
  38. This comment has been removed by the author.

    ReplyDelete
  39. I like your blog, thanks for sharing. I love this information you shared with us. I am waiting for your next post. Keep it up.Malaysian civil procedure 2021

    ReplyDelete
  40. What divorce lawyers say and what they do can be very different outcomes. Although their intentions may be pure the cases can be quite complicated. Nonetheless, it is always better to have a dedicated and experienced divorce lawyer in your corner if you find yourself going through the divorce process.Personal Injury Attorney in Orange County

    ReplyDelete
  41. It is through our agreement and utilization of the insight held inside these four Laws of Life that will decide our encounters we will engage all through or lives. https://www.natlawreview.com/article/revised-ftc-guides-use-endorsements-and-testimonials-advertising-social-media

    ReplyDelete
  42. I can't help thinking about how much work this call will prompt?" More regularly than not, I got the feeling that my external IP lawyers saw my lawful worries as issues for them to address on an every hour premise, not as issues that could influence the benefits of the organization for which I worked. https://www.jdsupra.com/legalnews/developing-a-robust-doj-compliance-1065068/

    ReplyDelete
  43. Fascinating thing about Little’s Law. If someone who has been injured in a car accident say in Orange County, would a personal injury attorney in Santa Ana be what I research? Thank you in advance.

    ReplyDelete
  44. For instance, on the off chance that somebody affirms you have cash to pay him, and you don't, the asserter should demonstrate you have cash. It's not so much for you to demonstrate you don't have it. https://www.jdsupra.com/legalnews/are-you-a-financial-institution-glba-3843872/

    ReplyDelete
  45. The Mature degree of needing is about the individual needing to know a greater amount of who and what they are, and their motivation throughout everyday life. They need to communicate their real essence of adoration, inventiveness, overflow and liberality, https://www.natlawreview.com/article/crypto-laundering-bitcoin-money-laundering

    ReplyDelete
  46. I added it to my favorite’s blog site list and will be checking back soon.Best Car Accident Attorney

    ReplyDelete
  47. Assuming we could acknowledge that all prospects exist right now and stay centered in the Now of life, intentionally permitting the Laws of Life to uninhibitedly work through us, we would before long perceive that we are in a co-made world which we have moral obligation regarding bringing into reality.attorney medical malpractice
    malpractice attorneys near me

    ReplyDelete
  48. Sometimes we find ourselves in rare situations that make us suffer unfairly. Other personal circumstances such as bankruptcy, real estates and mortgage force us to hire lawyers. auto accident lawyer fresno

    ReplyDelete
  49. You have a genuine capacity for composing one of a kind substance. I like how you think and the way you speak to your perspectives in this article. I concur with your mindset. Much obliged to you for sharing.divorce lawyers Boynton Beach

    ReplyDelete
  50. Thanks for the blog loaded with so many information. Stopping by your blog helped me to get what I was looking for. rolet online

    ReplyDelete
  51. I have read your article, it is very informative and helpful for me.I admire the valuable information you offer in your articles. Thanks for posting it.. click here

    ReplyDelete
  52. You have a genuine capacity for composing one of a kind substance. I like how you think and the way you speak to your perspectives in this article.lawyer in Abu Dhabi

    ReplyDelete
  53. This comment has been removed by the author.

    ReplyDelete
  54. It is considered more complicated than many other simplified systems because there are several different courts within the system but not all have the same power of jurisdiction. https://www.bestdivorcelawyerdelhi.in/

    ReplyDelete
  55. At the point when an individual has encountered a physical issue because of the carelessness of one more party it is a generally excellent choice to talk with an in private attorney injury.

    ReplyDelete
  56. I am really extremely glad to visit your blog. Presently I am discovered which I really need. I check your blog regular and attempt to take in something from your blog. Much obliged to you and sitting tight for your new post

    ReplyDelete
  57. Yes i am completely concurred with this article and i simply need say this article is extremely decent and exceptionally useful article.I will make a point to be perusing your blog more. You made a decent point yet I can"t resist the urge to ponder, shouldn"t something be said about the other side? 먹튀검증업체 .
    zxdh

    ReplyDelete
  58. I unequivocally got what you mean, an obligation of appreciation is all together for posting. From an overall perspective, Total TV News Girl Service in Delhi I am a stunning store of genuinely glad to track down this site on the universe of Google

    ReplyDelete
  59. This is one awesome blog article. Really thank you! Will read on...
    محامي عقاري جدة

    ReplyDelete
  60. Bases of Ward: The main contrast that exists between the conventional English laws and the EC law on purview is the component of tact that the separate assemblage of law provides for the appointed authorities in deciding the jurisdictional issues. How to win child support modification

    ReplyDelete
  61. Here the absolute best DUI lawyers in the nation share their insight with other DUI lawyers. https://syglaw.com/family-based-visas/

    ReplyDelete
  62. When you can harm up a register of lawyers, take a gander at every lawyer's profile by tapping on their name, or by tapping on the cling to "More news . . ." that plays close to each enlisting.
    افضل محامي جدة

    ReplyDelete
  63. Perhaps those are two of the reasons that I turned into a lawyer, so I could take care of those circumstances. https://callcefali.com/

    ReplyDelete
  64. You have a actual capability for composing one of a type substance. I like how you believe you studied and the way you communicate on your views in this article. I concur along with your mindset. Much obliged to you for sharing.personal injury lawyer Utah

    ReplyDelete
  65. This comment has been removed by the author.

    ReplyDelete
  66. Try not to succumb to the lower rates for a less experienced lawyer, you will probably be paying more over the long haul through deficiency of potential repayment cash.
    FrouharLaw

    ReplyDelete
  67. In the event that your mortgage isn't enrolled in the land library under any circumstance, your bank might force a fine. toprankinmortgages

    ReplyDelete
  68. Organizations which offer types of assistance to lawyers and lawyer firms can give excellent connections to tracking down a decent lawyer.
    https://agpllp.ca/

    ReplyDelete
  69. Criminal lawyers are the ones who have practical experience in managing cases including people or associations with criminal claims to their name.
    http://frouharlaw.com

    ReplyDelete
  70. On the off chance that how much your legitimate question is tiny, for example, a case or grumbling by a client for $1,000 or less, employing a lawyer will be uneconomic. Sohovich Law

    ReplyDelete
  71. A guidance from legitimate consultant ends up being an extraordinary assistance to get a reliable criminal lawyer.
    https://agpllp.ca

    ReplyDelete
  72. TO DETERMINE IF A COMPANY HAS A RESPONSIVE CUSTOMER SUPPORT TEAM, YOU CAN TRY EMAILING THEM AND MAKING INQUIRIES. TAKE NOTE OF HOW QUICKLY THEY RESPOND TO YOUR MESSAGES AND HOW POLITE THEY ARE IN THEIR INTERACTIONS WITH YOU. THESE FACTORS CAN HELP YOU ASSESS THE QUALITY OF THEIR CUSTOMER SERVICE.TRAFFIC LAWYER





    ReplyDelete
  73. You can check in the event that they have a responsive client support staff on the off chance that you attempt to email them and make requests. Perceive how quick they answer to your messages and how respectful they are in their dealings with you. By these by themselves.Speeding Ticket Attorney

    ReplyDelete
  74. To dispose of a DUI accusation and keep on carrying on with an ordinary life, an individual ought to search for qualified lawyers.
    FrouharLaw

    ReplyDelete
  75. Real estate is fundamentally the deal, buy, and move of homes, structures or some other business property and exceptionally severe laws are eased for real estate exchanges.
    realestatelawyerottawa.ca

    ReplyDelete
  76. This comment has been removed by the author.

    ReplyDelete
  77. To guard corporates or people who are denounced of such criminal direct, they need to name a decent criminal lawyer.
    stephenjackcriminallawyer.ca

    ReplyDelete
  78. The MetaMask  Extension is your gateway to the exciting world of decentralized technologies and blockchain applications. Seamlessly integrated into your web browser, MetaMask empowers users with a secure and user-friendly interface to interact with the decentralized web, manage digital assets, and explore a multitude of blockchain-powered services.

    ReplyDelete
  79. Law operates as a framework that guides human conduct, offering a structured approach to resolving conflicts and promoting harmonious coexistence. These legal frameworks vary across jurisdictions, ranging from common law systems that rely on precedent and judicial decisions to civil law systems based on codified statutes. International law further extends this framework, governing relationships between sovereign states and addressing global issues such as human rights, environmental protection, and trade agreements.Đăng ký kinh doanh

    ReplyDelete

  80. Playing with Little's Law in the realm of operations research and queuing theory can be both fascinating and enlightening, as it provides a fundamental insight into the relationship between system throughput, work in progress, and cycle time.luật sư Cam Lâm

    ReplyDelete
  81. Great Job I like You Post I have also written something on my website, You read it, you will like it. https://www.kavyamittal.com

    ReplyDelete