Looking back at my 2016: publications and media

Here is a reasonably complete collection of things written by me, interviews of me, book reviews about my book, and articles to which I contributed through interviews or quotes or data sets for the year 2016. It’s been a busy year, and rewarding in many ways.


My second book What’s Yours is Mine: Against the Sharing Economy was published by OR Books in November 2015, but I am including the book and related articles here, making it a “long 2016”.

  • US and UK edition (link), OR Books, November 2015
  • Canadian edition (link), Between the Lines Press, February 2016
  • German edition (Deins ist Meins): Verlag Antje Kunstmann
  • Spanish edition: Lo tuyo es mío, Taurus, November 2016
  • Simplified Chinese edition: (Ginkgo Book Co.)
  • French language edition (France and Québec): Ce Qui est à Toi est à Moi, translated by Hélène Rioux, Lux Editeur

Book chapter

Invited Essays

Reviews of “What’s Yours is Mine”


Quoted, and Airbnb data

Report: How Airbnb hid the facts in New York City

Together with Murray Cox of Inside Airbnb,  I produced a report on Airbnb’s removal of 1500 listings in New York, just in time to make its public release of data look good.


Why is Airbnb offering a bonus for new hosts in Vancouver?

Here’s an odd thing. Airbnb has a new program in Vancouver, offering $250 cash bonus for first-time hosts. It’s odd for two reasons. First, the company has been under pressure for exacerbating the city’s housing affordability crisis (Vancouver’s housing market is the most expensive in North America), so this looks like asking for more trouble. Second, Airbnb in Vancouver is already going gangbusters, so why does Airbnb feel the need to pay out to attract new hosts?

Here is a chart that shows what I mean by “gangbusters”. The y axis is the total reviews per month for a set of North American cities, with Vancouver picked out in bold red. The total number of visits is probably about one-and-a-half times this number, so it’s a measure of overall Airbnb traffic in the city. You can see there is a seasonal trend, with traffic dropping off over winter and picking up again in summer, but it’s pretty clear that this summer’s peak is well above last summer for most of these cities. Vancouver is now running at well over twice the volume of last year. (Click to expand, and hit the back button to return to the post)

vancouver_1But there’s another way of looking at this growth. Vancouver is again highlighted in bold red in the chart below, which unpacks the overall traffic shown above. The x axis is the number of listings in the city, and the y axis is the average occupancy rate measured as the number of reviews per month per listing. Multiply them together and you get the total traffic for the city.

For most cities the trend is to more listings, with the occupancy rate going through the same seasonal trend we saw up above. (Although Philadelphia and Chicago are not doing so great, and San Francisco (the curly green line) seems to have hit a limit of listings, probably because of the drastic action Airbnb is taking to legitimize itself in that city. But that’s another story.)


An increase in traffic can come about two ways: more listings, or higher occupancy, and there’s a bit of a trade-off between the two. So Toronto and Montreal (yellow and brown) have seen a rapid growth in the number of listings and the occupancy rate has grown significantly, but not massively. Meanwhile Vancouver has not seen such a rapid growth in the number of listings, but the occupancy rate is growing like topsy.

Now if a hotel was counted as a single listing it would be way to the top left of this chart, while Airbnb wants to claim that its hosts are only occasionally renting out the place in which they live — which translates into the bottom right. The fact that Vancouver listings are getting used more often could be bad news for Airbnb in its battle for legitimacy, so if it can attract more hosts they may take up some of the slack and move the line out to the right and down a bit.

To step back a bit, you do have to wonder if “bottom right” or “top left” makes much of a difference from the actual affordability and neighbourhood impact perspective. If you live in an apartment building and every other person rents out their place once a month, that’s the same impact in terms of traffic, extra utilities and the other things people complain about than a small number of people renting out their places all the time. And thousands of tourists staying in a small neighbourhood will have a similar impact (good and bad) in some ways if they are scattered across many listings or huddled together in a few. And what about the impact on house prices in high-traffic hotspots? It’s not obvious to me that a large number of low-occupancy listings has less of an impact than a small number of high-occupancy listings, though I could be convinced either way.

Anyway, I feel pretty confident that Airbnb is making its offer to offset the bad image that goes with the high-occupancy rates that Vancouver is now experiencing. And if there’s an offer for Seattle hosts, well that will confirm my suspicions.

Update: Thanks to Caroline O’Donovan for pointing me to this: an Airbnb host promotion in Seattle. Suspicions confirmed!

Airbnb in Lisbon: a few corrections

Airbnb just posted one of its charming city reports providing an Overview of The Airbnb Community in Lisbon and Portugal. The summary is here and the full report is here. At the prompting of some Lisbon urban geographers and activists concerned about the damage Airbnb is doing to the historic centre of their city, I’ve done some surveys of Lisbon.

The Airbnb report, as usual, presents some concrete figures, leaves out some other figures, and also presents a lot of figures that are not very interesting at all. It does so with the company’s traditional absence of supporting data or methods. Let’s look at a few of the most important.

Airbnb: “More than 4,500 hosts shared their space on Airbnb last year”

My results: Between May 2015 and May 2016,  I identify 4633 separate hosts who have properties with reviews. There are over 6000 separate hosts with listings on the site. The Airbnb statement confirms the data I have collected.

Airbnb: 72 percent of hosts in Lisbon have only one listing and hosts have lived in the city for an average of 25 years

My results: In my most recent survey, 71% of hosts have only one listing, confirming Airbnb’s statement.

What Airbnb doesn’t say: 65% of listings in Lisbon belong to hosts with multiple listings. The majority of listings in Lisbon do not belong to regular folks who use the site only to occasionally rent out the home in which they live. The number of “multiple listing” hosts is growing even faster than the overall number of listings. The total number of listings almost doubled between May 2015 (5600) to June 2016 (over 10,000), and the percentage of listings belonging to multiple-listing hosts has grown from 59% of the total to 65% of the total. To me, this “percent of hosts with only one listing” is always the most deceptive of Airbnb’s phrasings, and in the case of Lisbon it is particularly misleading.

Airbnb: A typical listing in Lisbon is shared for 76 nights a year and more than half of all listings in Lisbon are rented for fewer than 90 days.

My results: I don’t have reliable occupancy data, but this claim also is noticeable for what it doesn’t say. There are about 2,000 Lisbon listings with no reviews at all: clearly a host with no guests causes no problems and makes no money, but using a median value (the “typical” listing) gives each of these listings equal weight. What is of interest is those at the top end: and of course there is not much said here. We can infer that almost half are rented for more than 3 months in the year, but we don’t know the concentration at the top end.

What we do know is that the areas with most listings (Santa Maria Maior and Misericordia) have a disproportionate share of the business. Between them, they have about 40% of the listings but well over half of the visits, and (with prices there being more expensive) an even bigger share of the revenue. You can get a better idea of what this means by looking at the maps here (taken from my listings page), and download a full set of listings with each one:

Airbnb’s continued presentation of partial and biased “data” about its activities in cities around the world shows their lack of interest in accountability and, ultimately, their lack of interest in the cities where they operate.

Airbnb in Barcelona: two readings

A story on Ada Colau, who may be the world’s most radical mayor, hjighlighte how Airbnb can create problems for the cities where it operates:

Colau’s stated priority is to move Barcelona away from what she considers “massified tourism”, with no thought for sustainability, strategic planning or input from the public. “Until now, all we have had were private initiatives doing what they wanted,” Colau told me. “This has led to a model that is out of control.” She added: “We suffered the same short-sighted model here with the real estate bubble. We are trying to prevent the same mistakes happening again with tourism.”

For a detailed look behind the scenes, Albert Arias Sans and Alan Quaglieri have a new paper called “Unravelling Airbnb: Urban Perspectives from Barcelona” (sadly, login required). They investigate the claims made in Airbnb’s “reports” on the city and show each of them to be false:

Airbnb claim: The vast majority of Airbnb accommodation is located outside the areas with major concentrations of hotels.
Arias/Quaglieri: There is a strong correlation between Airbnb listings and the presence of hotels. Airbnb supply is located to a large extent in the same neighbourhoods as hotels.

Airbnb claim: Airbnb focuses on a new type of traveller seeking the authentic to immerse themselves in other cultures.
Arias/Quaglieri: Analyzing languages spoken by hosts: the composition of the Airbnb host community is different from the profile of the area as a whole. 
Airbnb appears as a field for the ‘cosmopolitan consuming class’, where hosts and guests share a similar approach to the city around a ‘cosmopolitan sense of local’ from which a large proportion of the rest of the residents of Barcelona are excluded.

Airbnb: proceeds from Airbnb allow hosts to cover their basiexpenses and reach the end of the month
Arias/Quaglieri: Airbnb hosts are not representative of the local communities. They are far more educated, have fewer children, and live in less-crowded households. While Airbnb hosting may help solve the prolems of people living in middle- to upper-class neighbourhoods, it is not a resource open to those in the poorer neighborhoods.

A really interesting read, which is a significant step forward in the debate about Airbnb’s impact on the major tourist centres.

Regulating the Sharing Economy

A long overdue post.

There is no slowdown in the debates about how to regulate Airbnb, Uber, and other Sharing Economy companies, as city after city in country after country faces up to the challenges of how to deal with these new actors. If only there were a clearly thought-out, well-written work that spelled out the issues involved, provided a framework in which to think about how to respond, and provided a useful set of recommendations that provided the starting point for regulatory ideas.

Well luckily there is.

Vanessa Katz’s “Regulating the Sharing Economy” was published last September the Berkeley Technology Law Journal. I heard about it at the time (thanks Chris Hoofnagle), but I was just going through final edits on “What’s Yours is Mine” and did not have a chance to write about it. I assumed someone else would, but a quick Google suggests that it has been overlooked. This is a shame. If you are interested in the topic, I strongly recommend it.

Now I am not a lawyer, still less a legal scholar, so I don’t really know the standards that apply to law scholarship, but as someone concerned with the topic I can say this: there are proposals for regulation that have been picked up and become part of the public debate (eg from venture capitalist Nick Grossman,* self-regulation proponent Arun Sundararajan,* Tim O’Reilly*), and I learned more from Katz’s piece than from any of these. It’s one of the few articles I’ve gone back to over and over again because Katz offers a way to think through the issues, to go beyond the too-easy claim that new technologies and new businesses need new rules, and to think about what’s really new, and what’s left unchanged.

A good starting point is to ask why we want to regulate some industries and not others, and Katz identifies a few principles that explain why we have a public interest in some private transactions. One class is “special relationships” in which the consumer is particularly vulnerable, and when additional burdens are placed on the service provider:

  • Relationships that pose potential health, safety, and financial concerns for consumers: landlord-tenant relationship being one example.
  • Relationships in which service providers have a disproportionately strong bargaining position: innkeepers and “common carriers” such as taxi drivers are required to accept all customers without discrimination. It’s a constraint on business, but one that is justified by the vulnerability of the customer.
  • Relationships in which the service provider is the “least-cost  avoider” – the party who can adopt precautions against a certain risk at lowest cost. Katz does not spell it out, but these situations are related to markets with asymmetric information: to keep the market working the service provider (as least-cost avoider) is required to guarantee certain standards: product liability being an example.

Sharing economy companies are quick to say that many existing regulations do not apply to them, but Katz is one of the few who asks the other question – what regulations are needed to deal with new challenges raised by the platform companies. Among these are reputation systems and their lack of appeal / process, privacy (a big deal when we start talking about in-car cameras, as well as customer data), and surge pricing (what happens when Uber offers personalized pricing based on your phone battery levels?)

All in all, an excellent read.

Airbnb data collection code and city stats

Over the last couple of years I’ve continued to tweak my Airbnb data collection code and run it against a number of cities. Anyone interested can see a partial list here, and if there’s a city you would like me to post data for, you can make a request here.

Some time ago I made the GitHub project private, as there’s obviously a potential for Airbnb to identify patterns and shut down attempts to scrape data. But enough people keep asking for it that I’m opening it up again, and you can find it here if you are interested. I make no claims to elegance or good practices in the code, but it’s worked for me.


Wrapping up: personal notes on the Airbnb report

Looking back at the Airbnb report that Murray Cox and I did earlier this month, now that Airbnb admits we were right

It was the beginning of December when Airbnb released data about its listings in New York City,  but it was early January before I had time to properly compare my own data to theirs. Pretty soon, I noticed an anomaly: what looked like a significant jump in the proportion of single-listing hosts between two surveys I had carried out, either side of the November 17 date Airbnb chose as a seemingly-random snapshot of their business. Murray Cox regularly collects data on Airbnb listings too at Inside Airbnb, so we talked about it. He looked at his data and thought he saw the same. So that’s interesting, we thought…

Then it was several weeks of questioning. We looked again and again at data reliability, we checked and cross-checked calculations, and we mulled over alternative explanations.  There is good reason to expect Airbnb to be misleading: there is $25 Billion in fortunes to be made through a good IPO, and that’s a lot of pressure to make things look better than they are. But incentives are one thing, and reality is sometimes another. Airbnb routinely calls our data sets inaccurate (see here and here, for example), and even though comparisons to Airbnb’s own selective data releases have made us fairly confident, I did worry that going big on a story may set us up for failure and embarrassment if we had missed something obvious.

First we asked ourselves: if these listings were actually removed, is this a story? Yes, we thought. If Airbnb removed listings immediately before making a “public data release” and never once mentioned doing so, it seemed like a clear case of using data to mislead, and given the high profile of the company’s original data dump (two New York Times stories, and many others) someone should be interested.

Can we prove that the changes are not just noise? I scan the Airbnb web site for NYC periodically, but a survey I did in early November had given bad results (for boring technical reasons) so the bracketing data sets I had were from early October and early December – a bit too wide for comfort. But Murray’s data has proven more reliable than mine, and (tipped off by Ariel Stulberg of The Real Deal) he had run an additional survey on November 20. His data confirmed what I’d seen and more — clearly there was something unusual that happened in early November.

Next: are our calculations correct? Comparing Airbnb data sets on different dates is tricky because there is always significant churn on the site — a lot of people put up a listing, get little interest or decide it’s not for them, and leave again. So I did my own calculations twice over (once in SQL, once using python pandas), and Murray did his own, and we compared, until we came to feel confident in them.

And what about alternative explanations? Running similar calculations on a number of other cities (thank you Jupyter notebooks) showed nothing of similar size. Even the previous known purges (like April 2014) did not show up quite so dramatically. Given the timing, we were pretty confident that the change was prompted by Airbnb removals, but who knows?

Finally: if Airbnb is removing “bad actors”, isn’t this a good thing? After talking it over with people I respect (thank you Lynne) we agreed that the big problem is one of trust. I managed to get the last word in the New York Times story on our report: Airbnb’s business model depends on changing regulations in cities around the world, and so cities need to be able to trust Airbnb. By hiding what they did, Airbnb is acting in an untrustworthy manner. Their “Community Compact” (actually a unilateral document, not a compact) commits Airbnb to co-operating with cities and being transparent: this action was neither co-operative nor transparent.

So several rounds of edits later, and after many attempts to format graphs so as to put the message in a clear fashion, we released our findings as a report, and it got more coverage than I could have expected. I admit I was nervous about Airbnb’s response: a bad calculation or an overlooked reasonable explanation could leave us looking pretty stupid.

In the first story (in the New York Daily News) “Airbnb dismissed the findings, saying through a spokesman that ‘listings come on and go off throughout the year. We routinely review our listings to ensure guests are having the quality, local experience they expect and deserve’.” The way I read that, Airbnb is saying the changes we saw are just regular churn in the business, and implicitly denying that the company did anything special in that time. The “spokesman” also said that “The report also focuses on the busy marathon and Halloween weekend, when listings spiked”; a claim the company repeated to The Guardian.

After a brief panic and a little reflection, it was clear to us that this explanation does not hold water. We hadn’t seen a spike in overall listings, we had seen a thousand more listings vanish from the platform than during other months, and almost exclusively these extra vanished listings were owned by hosts with multiple listings: there’s no reason for any special event to have such an effect.

As the day went on and coverage spread, Airbnb obviously got their act together and came up with a standard response. For example, here is what they sent to Fusion’s Kristen V. Brown:

“The facts are clear for all to see—the vast majority of our hosts are everyday people who have just one listing and share their space a few nights a month to help make ends meet. Airbnb is an open people-to-people platform where listings come on and go off throughout the year. We’ve also done significant work to educate our community about what is in the best interest of their city and we routinely review our listings to ensure guests are having the quality, local experience they expect and deserve.”

The company provided one other piece of updated information, which was to share “a partial snapshot with Fortune of its New York City listings as of Feb. 8 that shows that 94% of hosts there only have one listing.”

The paragraph is fluff, sprinkled with generalities. The number they give (94%) actually matches what Murray and I had found rather than countering it (Figure 1 in the report). This response again made me feel more confident that we were on the right track.

Still, I confess it was pretty sweet when, on Wednesday morning, Airbnb changed its tune. The company sent a letter and an FAQ to New York State representatives and posted the two documents on its site. I first heard of these documents from the above-mentioned Kristen Brown. Here is the key Q&A:

Did you remove listings from your community last fall?

Yes. We issued our Community Compact in November. Throughout November, and consistent with our Compact commitments, we removed roughly 1,500 of the 37,000+ Airbnb listings in New York City in an effort to remove listings that appeared to be controlled by commercial operators and did not reflect Airbnb’s vision for our community. 622 hosts were impacted, including 375 (60%) that had 2 or more listings removed.

The company has changed its tune, and conceded that it did indeed remove listings (and did not tell anyone about doing so). Fusion’s report had a great headline:

Airbnb admits that it purged 1,500 unflattering New York listings right before data release

The debate continues, of course. Working with Pat Clark of Bloomberg, Murray Cox has shown that some of the ejected listings have already started returning. The question of whether Airbnb’s own “vision for the community” is a sufficiently precise and legitimate criterion for removal will be debated (hint: No). But for now, I’m happy to celebrate being right.