How not to write a wine report

I do not usually do this sort of thing, but this time I am going to name names.

Let me explain. I used to teach university students about data analysis and presentation, and one of the exercises for those students was being given a series of published graphs and tables, and then being asked to find the inconsistencies (which I had previously found for myself). The idea was to show them real examples of all the ways one can go wrong when dealing with data, so that the students would (hopefully) be a bit more careful themselves, in their own future professional lives.

However, my examples were always kept anonymous — there is no point in fingering a few practitioners when the problem is actually widespread. We all make mistakes, and we don't necessarily expect to be pilloried for it, especially when most other people are also making the same sorts of mistakes.

In this post I am going to do the same exercise, but this time I am going to tell you the source of the errors, because they are all in the same wine report:

The Irish Wine Market Report 2018, produced by Drinks Ireland.

If you want to try the exercise for yourself, then stop reading here, and go read the report, instead. Make your own assessment of how many inconsistencies you can find; then come back here to see how well you did. Otherwise, read on now.

I have included a small part of each table or figure, to illustrate my points.

My comments

Page 5

The Wine Sales data are apparently in “millions”, but what are the units? Bottles? Liters? Euros? It turns out (as shown on page 8) that they are cases of wine. So, “0.2” ≈ 200,000 cases of wine.

Page 6

The Excise Receipts are apparently in “€”, but that cannot be right. Even the excise itself is €3.19 per wine bottle (the highest in the European Union!). Given the number of bottles per year (pages 5 and 8), I suspect that the numbers are actually each “million €”.

Page 8

The Country of Origin table has a duplicated column. The column is headed “2017”, but it contains a copy of the data from the “2018” column.

Furthermore, some of the columns do not sum to the “Total” given. The worst instance is the “2015” column, where the “Total” provided is 296 cases less than the sum of the numbers given. This, incidentally, is the error that used to most surprise my students — that, in the modern era of computer spreadsheets, people still can’t add up.

Even more inconsistent is that the data given on page 5 do not all agree with the Totals shown in this table. Notably, for the year 2000, page 5 shows 4.8 million (not 4.48 million, as shown here), and for the year 2013, page 5 shows 8.9 million (not 8.22 million, as shown here).

Page 9

The Percentage Share table contains some wrong numbers, based on the original count data shown on page 8. This occurs once in the “2016” column and four times in the “2000” column — the biggest difference is “2.9%” (shown here) instead of 3.6% (calculated from page 8).

Also, the number of decimal places for the bottom two rows is inconsistent, with 1 decimal place for most of the columns, but 2 places for the “2000” column and none at all for the “2013” column. Furthermore, the data for the bottom two rows shown in the “2018” column sum to 100.5% (not “100%”, as shown), which happens because both numbers are wrong (they should be 37.2% and 62.8%, not “37.8%” and “62.7%”). The same pair of numbers for column “2016” are also incorrectly rounded. Once again, all of this is based on the count data shown on page 8.

Page 10

First, what on earth is an “Excise: Tax on Tourism”? Excise taxes are placed on goods where the government doesn’t want you to overdose, like tobacco and alcohol. So, in Ireland each bottle of wine effectively has a minimum price, which will be equal to the excise duty — costs and profit are added to that price. So, what has tourism got to do with this?

Anyway, the reference to “HL Excise Rate”, does not make sense. The rates shown in the table are per bottle of wine. I suspect that the “HL” stands for “hectoliters”, which is how excise rates are usually quoted officially (see Excise duties in the EU), but it has no relevance to this table.

Page 13

Finally, I freely admit to being mystified by the High Excise Rate Tables. I have been unable to perform any calculations that will produce the numbers shown in this table. As far as I can determine, there is a constant €3.19 excise rate and a constant 23% value-added tax, but that information does not lead me to any of the numbers shown here. To me, there has been a complete failure to communicate with me, in this instance.

Conclusion

I always emphasized to my students that: (i) I would like them to get their reports right, and (ii) if they can't do that, then they should at least make them consistent. And when they are reading the literature, they should make sure that other authors have done the same — it is the first line of defense against false information. I still think that this is so.