The Giz UK Xmas Index: Using Data To Measure How Christmassy Christmas Is

By James O Malley on at

When does Christmas actually begin? Christmas purists might say the 25th December - the official first day of Christmas - but unless you’re a Piper piping, or one of a number of Maids-a-Milking, we know that’s bullshit.

In the weeks leading up to Christmas, we’re slowly subsumed by Christmas fever: The adverts begin in September, and office Christmas parties might even happen in late November, if you work for a particularly tight-fisted company. Some absolute maniacs put their Christmas tree up on the 1st December rather than maybe a week before, like normal people.

So as the year slides to a close, there’s always sort-of a persistent Christmas feeling. And this made us wonder: When does Christmas truly begin? Is there a way to measure Christmas feeling? Can we use data to inform when is the acceptable time to blast out Do They Know It's Christmas on the office stereo?

We think we’ve found a way. Presenting to you: The Gizmodo UK Christmas Index.

What is it? You know how stock exchanges, like the FTSE or the Dow Jones, boils down tonnes financial trading data into just one number, which serves an indicator for the whole economy? We’re doing the same thing - and our Christmas Index will be a single number, which when it moves up and down will give us an indication of just how damn Christmassy things are feeling.

What data are we using to calculate this number? Like the FTSE is made up for the top 100 companies, we’ve taken a pool of 145 Christmas songs from a popular Christmas playlist, and we’ve built a bot that will automatically monitor their popularity on Spotify. This includes everything from O Come All Ye Faithful to Frosty the Snowman and All I Want For Christmas Is You.

Spotify’s internal system gives each song a “popularity” score out of 100 - this score is based on a fairly opaque algorithm, though it is believed to be based on both the total number of plays and how recently those tracks were played. In other words: It is exactly what we’re looking for. The Index score will be the sum of all of these scores.

So the theory goes that as we approach Christmas, more people will be listening to Christmas music - and this will act as a good proxy for overall Christmassyness.

When Is It Appropriate To Listen To Christmas Music?

We’ve been running the Christmas Index bot since October 24th - which gives us over a month of data. So here’s a chart of what the Christmas Index has been for each day since we started - which reveals that Christmas doesn’t appear to arrive as a big bang, but as more of an incremental process. You won’t wake up one day and suddenly there’s Christmas music everywhere - it’ll just slowly start to transform your world without you noticing. A bit like the slow erosion of democratic norms in the Trump era.

Unfortunately at this early stage we don’t have much data to compare to - so we can’t predict exactly how Christmas-tastic things will get in advance of the big day. Nor can we predict when Peak Christmas will occur. Of course, it might seem obvious that it will be on the 25th December - but perhaps this data might soon reveal that it is earlier, as by the time we’re opening our presents everyone is sick of Ding Donging Merrily On High.

Similarly, unfortunately due to the opaqueness of Spotify’s algorithms we can’t tell exactly how many, or what proportion of people are currently jingling their bells, but we can tell that significantly more people are than were in late October. And certainly the rate of Christmas appears to have picked up too - the little notch you can see on the graph above in late November is Thanksgiving in America - a day, it seems, when people switch to Christmas listening. And after that holiday, the amount of Christmas in the air appears to be increasing at a greater rate.

(And yes, on the 9th November our computer tracking all of this data annoyingly crashed, but it feels pretty unlikely that everyone suddenly started Decking The Halls for one day only.)

Checking In

So what is the official Gizmodo UK Christmas Index at today? Today we stand at 6915 points - that’s up from 6475 a week ago (an increase of 440).

The biggest individual climber over the past week: 2000 Miles by The Pretenders - which is 8 points more popular. If this were a financial market, you should definitely buy The Pretenders stock now.

And the biggest fall? Umm. Jingle Bells, which is actually 1 point less popular than last week. So no love for the classics, it appears.

So this is the Gizmodo UK Christmas Index. Pretty neat, eh? It’ll be fun to see just how dramatically this increases over the next few weeks: Will Christmassyness plateau, or will it peak massively higher than now? We’ll be checking in regularly to find out.