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Thursday, December 06, 2007

Multiple device ownership - crunching some numbers

A regular theme that I have to deal with is multiple mobile device or SIM ownership. Statistics are very fuzzy on this - you get the usual estimates of 120%+ penetration, but very little analysis of what that means in reality.

Vodafone occasionally tries to estimate the level of multiple SIM ownership in its markets, and I commented on a survey on the UK market recently which seemed to suggest 1.6 SIMs per person, but definitions seemed questionable, eg with penetration of phones among children.

I thought I'd try and come up with some slightly harder numbers.

The UK has 70m SIM registrations at the moment, and 60.8m people, with a demographic breakdown given here. Last year, Carphone Warehouse did some analysis of mobile penetration among children up to age 12, while Ofcom has some great research (figs 15 & 16) on the proportion of adults who personally use mobile phones.

This yields the data that 86% of people >15 years old are active users. This is heavily skewed by older people - only 52% of over-75s use mobile in the UK. Among children, from the CPW study there is near-zero penetration among 8-year olds & below, 20% @ 9, 50% @ 10, 70% at 11 and 90% at 12. Given the other data it seems reasonable for me to assume that about 93% of 13 & 14 year-olds are users. The youth data is a year old, so might have shifted slightly, but it's a good starting point.

Multiplying this all through by the population stats gives me:

Total UK Mobile Users = 46.4m individuals - ie 76% of the total population.
Total UK non-users = 14.5m (mostly young kids & seniors)
I'd estimate 1-1.5m SIMs are used in non-personal M2M applications (EPOS terminals, vending machines, wireless routers etc, but excluding laptops & PDAs which are personal devices).

So.... 69m personal mobile subscriptions among 46m active mobile users =

1.46 Mobile Subs / Active User in the UK.

This excludes UK citizens who have international SIMs as well (although probably some of the UK SIMs go abroad too).

What remains slightly unclear is the mix of people with 1SIM+Multiple Devices vs. Multiple SIMs+single device. ie the ratio between active subs/person and active phones/person. Travellers often put local SIMs into a single phone when abroad, but users who like phones for fashion reasons may swap a single SIM among multiple devices.

What this all categorically tells me is that the "one mobile device" philosophy is completely inapplicable in the UK. My rough estimates are

Zero Subs = 24% of all UK individuals
1 sub = 49%
2 subs = 17%
3 subs = 7%
4+ subs = 3%

Bottom line = a majority (51%) of the total UK population either has zero mobile subscriptions, or multiple. People with just a single active SIM are actually in the minority (49%).


Ian Wood. Principal Wireless Foundry LLP said...


Think that you are close but need to make a few adjustments.

First I would suggest that you discount the active sim number for the UK and then run the numbers again.

Then I think that you need to look at the M2M numbers and increase those.

Run the numbers again and you should get a number closer to the 70% rate that is use internally by two of the five UK networks.

Anonymous said...

in the uk the definition of active user is vague to say the least. its very very easy for an operator to inflate the number of so-called "active" prepay sims, ege mail out 500000 "free" sims expect 10% to activate and hey presto 50000 extra users at the drop of a hat just in time for quarterly results! and never mind "sleeping" prepay customers who use the handset once every 6 months... or the Machine-to-machine SIMs...or the "active" but unused business SIMs....

so your initial premise that the UK has 70m SIMs is basically wrong. and you know what? vodafone know that. carphone know that (and if you call that link "analysis" you're in trouble). EVERY operator knows that.

but just occasionally we get schmuck analysts to give us their opinion. hey don't get angry, it puts food on your table.

Dean Bubley said...

Digital Evangelist - thanks. Constructive comments. This wasn't intended as a definitive analysis, more about highlighting some of the vagaries involved.

Although certain people at the operators have obviously gone through this thoroughly (at least I'd hope so), I'm sure you're aware that many external observers often fail to scrutinise data at all & just assume "subscriber = user".

The GSMA is a typical culprit:
http://www.gsmworld.com/news/press_2007/press07_48.shtml includes the phrase "serves more than 2.5 billion people"

Anonymous - You're obviously having a bad day, based on your couple of comments on recent posts. Hope it works out for you soon.

I've written posts before on how operators play with their reported numbers, and also seem happy to have observers misinterpret them:


For what it's worth, some operators define "active" as generating a billable event in the past 3 months - but that can also include inbound calls & SMSs as well as outbound.

Anonymous said...


interesting: rather than admit an error in your original post you choose to refer to an older post which is only tangentially relevant (and itself filled with errors)

the point is: 70m is wrong. plain wrong. and you would know this if you actually had any understanding of what you were talking about. the fact that operator "fudge" numbers (ie release inflated bases for investor purposes using antiquated metrics) is irrelevant here. because even if they do, you, as someone who claims to be an analyst should be able to look beyond the published data. isn't that what your customers pay you for?

"For what it's worth, some operators define "active" as generating a billable event in the past 3 months - but that can also include inbound calls & SMSs as well as outbound.

thats how operators define "active" for reporting purposes.

Of course you know the difference between a 30day base, a 90day base and a 180 day base? and you know the relevance?

thought not.

Dean Bubley said...

Anonymous - my customers don't pay me for quick back-of-the-envelope calculations I publish for free on my blog.

However, they do pay me for facilitating discussion, and raising awareness of issues that are rarely discussed in public.

You'll also be aware that Disruptive Analysis' primary business is not in compiling general box-counting statistics.

I'm quite prepared to believe that the 70m figure is over-stated: I've used public sources such as Ofcom for that, given that this wasn't a detailed research study.

Clearly internal analysts at operators will have access to more accurate usage data on a per-SIM basis. Although they also don't know their customers' real behaviour quite as well as they'd like to think they do.

Perhaps you'd like to enlighten the world as to what you think the real number is? And while you're at it, perhaps you could explain why you seem so sanguine about distorting it for the benefit of investors and your regulator?

Any thoughts on the number of foreign SIMs owned and occasionally used by UK residents? Plenty of business travellers have a wallet-full of them.