Why you should ban incoming calls immediately – the MM1 Approach

by Ivan Mazour

608-03473363These days we have so many different forms of communication available to us. I use e-mail, Google Chat, text messages and phone calls on a daily basis, supplemented by shared notes on collaborative online tools to keep track of progress on various projects.

During the busiest and hardest time of my life – the Mathematics Tripos at Cambridge, words that will inspire awe and trepidation in anyone who has had to sit these exams and are now scarred with the stress they embodied – I found myself so overworked that I needed to implement a communications policy to make sure I could successfully complete my revision while still managing my companies and relationships.

My rules were as follows:

1. Emails were to be used when something was important and not time sensitive.
2. Text messages were to be used to draw my attention to something that was important and time sensitive.
3. Google Chat was the only medium to be used for communication that was not important.
4. Phone calls were not to be used at all, except for in the case of genuine emergencies.

This way if I was online and on Google Chat, then I wasn’t in the middle of concentrating on something vital, and so didn’t mind my attention being diverted onto random and potentially irrelevant matters. Important matters, on the other hand, would collect in my Gmail inbox and would get handled in one go at times I’d allocate specifically to that, several times a day. There would be no alert set for e-mails, neither on my computer nor on my phone, so I would do this according to my own schedule. If something was time sensitive, then I would receive a text message telling me to check that specific e-mail, and the text would have an alert which would interrupt whatever I was doing. I would read the text and make a decision whether the interruption was worthwhile.

I sent this policy to everyone I know, including my colleagues at work and to my girlfriend – http://www.tijanserena.com – who, as you can imagine, was not particularly impressed. However, being supportive, she came around to understanding my reasons behind it and helped me by sticking to it, as in the end did everyone else.

One of the courses I was revising for my final year exam was called Applied Probability, and part of the course was Queuing Theory. The concepts were both fascinating and directly relevant to this policy – and based on them I called this communications policy the “MM1 Approach”. The M/M/1 queue is a model of a single server (think a barista at Starbucks) who has tasks allocated to him or her on a semi-random basis and who takes a semi-random time to complete each one. There are two relevant numbers – lambda, which is the rate at which tasks are set, and mu, which is the rate at which they complete them. As long as mu is greater than lambda, everything will be fine. If lambda is greater than mu, then the number of outstanding tasks will grow to infinity – the barista never gets to go home.

Each of us is but a server, completing tasks. The older we get, the more tasks we get. Get married – lambda goes up. Have a child – lambda gets another order of magnitude. Mu depends on our discipline, and how efficient we are. Using lots of productivity tools, we can influence our mu by quite a significant extent. So by using the policy above, we increase it even more, while reducing lambda to the lowest level possible.

Consider what happens with most people. Their friends might send them an e-mail with a lolcat, or a link to an article online. Their colleagues are sending them e-mails about things that are very important, as well as other matters which are not. As they sit and try to complete an important task that requires commitment and concentration, every few minutes they allow themselves to be drawn away by the Pavlovian response – they hear the ping of an e-mail, and it is impossible not to immediately check it. With the constant distractions, the important work never gets done. And most of the time the distracting e-mails aren’t even that important.

Consider now the above approach. You can concentrate on any task, even if it’s one that requires a long period of unbroken concentration. E-mails are collecting in your inbox. Should something be time-sensitive, a text message arrives and its ping tells you to interrupt what you are doing and check your e-mails. You check your e-mails, and see not 200 mixed messages about lolcats and celebrity babies, but only the important items. You deal with them, one by one, and once it is done, go back to the important work you are doing. E-mail no longer rules your life. And more importantly, other people no longer dictate how you spend your time.

And it’s this idea that sits behind the title of this blog post. The most important thing I did during that period, and have continued to do since, is to ban incoming phone calls. Speak to any car salesman or estate agent – they know that the best way to close a deal is a phonecall. An e-mail may be dealt with, but it may also easily be deleted, or its response may be delayed. The decision is up to the person receiving it. A phonecall cannot – if someone picks up, they are at the mercy of the person who called them. Why should we let how we allocate our time depend so directly on other people? They do not know if we are in the middle of something important – but we do.

People don’t like to ignore phonecalls. They have the fear of missing out, in case the person was calling them to tell them something important. Alternatively they think it’s rude to ignore a call. But if it’s important, they will send an e-mail. They’ll find another way to get in touch. And what’s actually rude is someone interrupting your busy day with something they want to talk about, but you might not. People find it a bit strange when I tell them not to use my mobile number since I won’t pick up any incoming calls, but in the end they easily comply, and it does not affect my relationship with them, or my ability to get things done. I’ve taken back my life, and it feels great. Will you do the same?


Find out more on the about Ivan Mazour page.
And watch Ivan Mazour's TEDx Talk - "Why we shouldn't be scared of sharing our personal data".

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Rob O April 21, 2013 - 10:21 am

You have a phone so you only call people when its a genuine emergency? Isn’t a human interruption a valuable chance to interact? You can say no to salesmen or call friends back later. You probably could have politely refused 100s of phonecalls in the time it took to write an anti social blog about it…

Ivan Mazour April 21, 2013 - 10:33 am

Rather than responding, I’m going to point you in the direction of a post I think you would benefit from reading:


Varun April 21, 2013 - 3:23 pm

Don’t disagree with a lot of what you said but I think you fail to take into account the fact that different professions have very different methods of communication. For example, in consulting when dealing with a client, the golden rule is that face to face is always preferable, then a phone call, and lastly an email. In banking when dealing with other bankers in other locations, sometimes a phone call is 100% necessary to build a relationship. Etc

Ivan Mazour April 21, 2013 - 3:54 pm

Ah but I completely agree! Those are outgoing calls – I’m not against those at all. If you need to get something done then first it’s face to face, then Skype, then call and then e-mail is definitely the order, but in this case it is you taking the action and taking charge of the conversation. You’ve found the right time when you have no other tasks that are more important, and are choosing to spend that time calling a client. However when someone does that to you, then you end up on the receiving end, and that is what I am against.

Varun April 22, 2013 - 12:29 am

What if it is a client who is trying to call you?

Ivan Mazour April 22, 2013 - 6:14 am

Fair point – in any professions where you provide a service or have clients, you need to pick up your phone. Potentially then the plan would be to get so good at your job that you are in a position to start scheduling them, or move into a management role where you are no longer client facing. But yes, the post is based on the perception frame of someone running a tech company, so doesn’t apply all round.

Alex Zakharin May 23, 2013 - 6:01 am

Any system that is not bulky and too intricate for its user is a helpful one. If you save more time by following it then you waste by trying to chisel those who are around to understand it then you are on the right way. In those cultures where I’ve spent my life (Russian, British, French, Jewish) a personal touch and face-t0-face approach are of the most value but people are different and so are their rules.

Ivan Mazour May 23, 2013 - 6:09 am

I completely agree – I’ve only lived in two countries, the UK and Russia, but I have spent time in a number of different subcultures within both countries, and a face-to-face approach is an absolute must in all of them. A phonecall is an order of magnitude less efficient and creating real lasting relationships – the time is better spent on using other forms of communication in order to set up what will be a genuinely productive in-person meeting. I take your point about the potential time-wasting aspect of trying to get people to mould to the way you operate, but I find that if you take an option away from them, they simply use the next available one.

Alex Zakharin May 23, 2013 - 7:38 am

Yes, absolutely, as a rational creatures we tend to search for the next available option once the most convenient is not here so I can see lots of benefits in what you are saying. The reason I like your system that it does eradicate all the clutter and enables to boost productivity. Will try to increase my mu and work on the pesky lambda 😉

Katie Katie F January 31, 2016 - 9:42 am

Love this piece. I couldn’t agree more. Calls are intrusive and disruptive to a train of thought. How do you deal with your voicemail though…?

Ivan Mazour January 31, 2016 - 10:35 am

Thanks Katie! Definitely no voicemail – it’s really inefficient as you can’t scan, you have to listen to the messages one by one. So I just don’t have it switched on.

Steve Tuck June 6, 2016 - 8:00 pm

Yes! lambda < mu and life is good.


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