Stats Chat

Two excerpts from Gavin White’s  SAYit blog:

The flag

The specific question was “do you think the New Zealand flag should be changed?”.  The answers were:

• Yes 19%
• No 77%
• Unsure 4%

And on conspiracy theories

…the moon landing:

• 20% of us think that it’s likely that the United States of America government staged or faked the Apollo moon landing (5% very likely, 15% somewhat likely)
• 74% think it’s unlikely
• 6% are unsure or haven’t heard of this conspiracy before..

In response to a reader request, here are the same bus service maps as for Auckland. Again, click for big PDF files so you can zoom in.  I think these include non-bus transit, but I’m not completely sure.

Hours per day with at least six transit trips within 500m

Hours per day with at least 12 transit trips within 500m

In the Wellington region it seems that people who have any bus service have a useful amount.

The region as a whole has a smaller proportion of people with good public transport than Auckland region (7% in the top category, 60% in the bottom), but if we restrict to Wellington City there are 17% in the top category, 26% in the next, and only 30% in the lowest.

[Update: Here’s a version with a 1km distance instead of 500m]

Ok, so the previous post is about Herald (Daily Mail) story on asthma research. As science reporting goes it’s no worse than usual for these Mail reprints. The reason for this second post is that I read the story again and thought about health reporting.

The story lead says

Eating fast food and consuming sugary drinks renders the most common asthma inhaler ineffective, a study warns.

 That is, the Herald is telling people their emergency asthma inhaler will not work if they eat certain foods. There’s no suggestion of what to do instead in an attack or who to call for help. Even if the claim were true, that would be irresponsible. When it’s just linkbait, it’s fscking appalling.

The Herald’s lead

Eating fast food and consuming sugary drinks renders the most common asthma inhaler ineffective, a study warns.

This is two studies. One looked at a ‘dietary inflammation index’ and whether people with higher values were more likely to be asthmatic. It did not look at inhaler effectiveness at all.  The dietary inflammation index does not measure ‘sugary drinks’; it treats all carbohydrate the same. It doesn’t directly measure fast food, though it does distinguish different types of fat.  Since the dietary inflammation index, according to the paper that proposed it, is relatively weakly associated with biological measures of inflammation,  the strong association seen in this study between the index and asthma may just mean that other factors are affecting both asthma and diet.

The other study looked at how salbutamol, the active ingredient of the Ventolin inhaler, was absorbed in samples of lung tissue in the lab. The amount of polyunsaturated fat affected absorption — but that wasn’t dietary fat and there weren’t any inhalers, or any sugary drinks.  Further research might show this translates into real differences in inhaler effectiveness, or it might not.

So, while there is actual science described in the article, there is almost no support for the lead. No inhalers, no sugary drinks, no fast food.

You might also wonder why the Herald is getting a comment from Asthma UK for research presented at a conference of the Thoracic Society of Australia and New Zealand. Or not.

Bus commuter services can be very useful in reducing traffic and parking congestion in the city center, but reducing the average number of cars per household requires buses that are available all the time. I used the Auckland Transport bus schedule data and the new StatsNZ meshblock data and boundary files

Here’s a map of Auckland showing how many hours per day (on average) there are at least six bus trips per hour stopping within 500m of each meshblock (actually, within 500m of the ‘label point’ for the meshblock).

On a single road, six trips per hour is one trip in each direction every twenty minutes. The dark purple area has this level of service at least 16 hours a day on average. (Click for the honking great PDF version.)

For twelve trips per hour (eg, one every twenty minutes on two different routes) the area shrinks a lot

The reason for using meshblocks in the map is that we can merge the bus files with the census files. For example, for Auckland as a whole, 50% of the population is in the grey busless emptiness, 17% in the 8-16 hour tolerable zone, and 12% in the pretty reasonable 16+ hour zone.   People of Maori descent are more likely to be unbused (60%) and less likely to be well bused (8%), as are people over 65 (60% in the lowest category, 9% in the highest).

Recent (<10 years) migrants like transit: 18% of us are in the good bus category and only 40% in the busless category.

The flipside of failing to question numbers is assuming that anyone who does question them is correct (from US journalism/editing blog headsup)

Hence, even though in this case it’s an out-and-out lie, “another phony poll” doesn’t just resonate around the echo chamber; it puts a bug in the grownup world’s ear too. It looks like what journalism is supposed to be doing. Polls are suspect anyway (being based on data, which is inferior to gut feelings and news sense), and catching a fake one is a triumph of  the common man over the spinmeisters

• Vox.com is live, and looks very promising. In particular Ezra Klein’s piece “How politics makes us stupid“
• Columbia Journalism Review reviews vox.com
• StatsChat’s upstairs neighbour, Richard Easther, has a piece on how to deal with cranks
• A summary of the NZ Scientists Association conference last weekend

Congratulations to Myles Thomas who is our Stat of the Week winner this week for nominating the following poll question:

“Statistic: In the latest 3 News-Reid Research poll, when asked if David Cunliffe’s actions were worthy of a Prime Minister, 65 percent of voters, almost two-thirds, said “no”, while only 27 percent said “yes”.

As Russell Brown points out – this question is ludicrous. What does that even mean? That people think he’s not fit to be Prime Minister? That it was an unworthy action of someone who aspired to be Prime Minister one day? It’s actually a hard question for even a Cunliffe supporter to answer “yes” to. As a bit of emotional framing it works well, as a research question it’s bullshit.

This seems to be a news company engaging in dodgy push-polling and the claiming the inevitable but meaningless result is news. Wrong on several levels.”

Each week, we would like to invite readers of Stats Chat to submit nominations for our Stat of the Week competition and be in with the chance to win an iTunes voucher.

Here’s how it works:

• Anyone may add a comment on this post to nominate their Stat of the Week candidate before midday Friday April 11 2014.
• Statistics can be bad, exemplary or fascinating.
• The statistic must be in the NZ media during the period of April 5 – 11 2014 inclusive.
• Quote the statistic, when and where it was published and tell us why it should be our Stat of the Week.

Next Monday at midday we’ll announce the winner of this week’s Stat of the Week competition, and start a new one.

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A nice animated GIF showing what difference a small amount of simple formatting can make to a simple table. You may need to click on the image.