Posts from September 2016 (33)

If you’d like to comment on or debate any of this week’s Stat of the Week nominations, please do so below!

There are stories on Stuff and the Herald about early studies of a potential Alzheimer’s drug. There was also a story on One News last night, but the video doesn’t seem to be up, and there’s one on Newshub.

The drug, adacanumab, reduced amyloid plaque buildup in people with early-stage disease. According to the most widely believed theory about Alzheimer’s, that could slow or even stop the progression of disease. And, as the stories say, if the treatment turns out to be successful in future trials, it will be a game changer.

We’ve never had an successful treatment that modifies the disease process in Alzheimer’s, but we’ve had a range of promising candidates that failed as soon the test went beyond biochemistry to improvements in memory or the ability to handle daily life.  Adacanumab might be different. Let’s hope so.

Auckland Transport released new patronage data, and FigureNZ tidied it up to make it easily computer-readable, so I thought I’d look at some of it.  What I’m going to show is a decomposition of the data into overall trends, seasonal variation, and random stuff just happening. As usual, click to embiggen the pictures.

First, the trends: rides are up.

It’s hard to see the trend in ferry use, so here’s a version on a log scale — meaning that the same proportional trend would look the same for all three modes of transport

Train use is increasing (relatively) faster than bus or ferry use.  There’s also an interesting bump in the middle that we’ll get back to.

Now, the seasonal patterns. Again, these are on a logarithmic scale, so they show relative variation

The clearest signal is that ferry use peaks in summer, when the other modes are at their minimum. Also, the Christmas minimum is a bit lower for trains: to see this, we can combine the two graphs:

It’s not surprising that train use falls by more: they turn the trains off for a lot of the holiday period.

Finally, what’s left when you subtract the seasonal and trend components:

The highest extra variation in both train and ferry rides was in September and October 2011: the Rugby World Cup.