## Bubbles of the same size

##### Sep 20, 2008

Frederic M. sent in this chart, together with his commentary.

He wrote:

Bubbles across rows have vastly different numbers but their circles are of identical size (or vice versa). It borders on the ridiculous that all bubbles of the US row have the same size... The question if teenage birth rates and teen sex are correlated cannot be eye-balled with this kind of display. The fact that you cannot compare across rows make this an instance of “chart junk”.

White spaces -- always dangerous.  Does lack of bubble imply no data or no abortions/sex?

Sorting -- this is what Howard Wainer called "Arizona first" with a twist (United States)

Loss aversion -- would U.S. readers be resentful if countries like Iceland are excluded?  A much reduced version comparing U.S. to say Canada, U.K, Japan and Germany may yield more information for the reader.

Sufficiency -- if all the data are printed as in a table, why do we need the bubbles?

Reference: "Let's Talk About Sex ", New York Times, Sep 6 2008.

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There is yet another major problem with this chart, and that is that teen sex rates are reported as percentages, and birthrates & abortion rates are reported as per 1000. At a first glance, the reader would think that for every 81 teens in the USA who have had sex (ever), 30 have had an abortion.

I'm guessing that the USA bubbles are the same size because the author is setting USA rates as the "norm" to which all other countries are compared (which is problematic in itself of course), and wants the reader to only compare down columns, not across rows. Was that your interpretation?

I concluded the same as laurelhd, that the intention was to show a comparison with the USA. The bubbles do not reflect the data directly but are relative to the USA

This explains the mismatch of data and bubble size and that the USA appears at the head of each column.

if comparison between countries was intended solely (down columns), why not pick few relevant countries and put them into the rows?
It's way easier to compare rows since that's how we are used to watch (read) ..

If you look at the original report, the "teenage abortions" column comes from a graph that has a matching column of "teenage births" with it, but they threw it away and got their teenage births from another graph that has more countries and two years. That goes beyond loss aversion, to being greedy for more data and damn whether the result is informative.

Uurgh! This is truly awful, and maybe crying out for a Gapcast-style bubble chart - say, sex on the x axis, birth rate on the y, abortion rate as bubble size and bubble shading to denote upward or downward trend in birthrate? Or maybe, colour by continent and present two graphs for the 1970 vs 1998 birth rate data. Only the 'interesting' points need to be labelled, so the large number of European data points could still be represented without overwhelming the rest. Iceland is interesting because it's one of the extremes.

I'm a little troubled by the weight placed on the 'sufficiency' rule; wouldn't this ultimately lead us towards presenting all data in tables with no graphs? Shouldn't a good figure be able to show us both an overview of the data, and more detail if we require it?

Kaiser:

Very interesting post. The New York Times usually does a much better job than they did on this chart.

I've posted on the value of this chart and generated a dot plot alternative here .

Kelly

Ummmmmmmmmmm. Maybe my english is not good enough but I think the problem starts with the title: "Let's talk about sex"
It is not too focused. Is it? Thats why they mix concepts, units of measures, countries etc. without consistency. That's what we all do when we just talk or chat (?) about things.
By the way this is a great page. Thanks.
Oscar

the post does not mention that this is an *op-ed* chart, made by a times columnist stating his opinion. op-ed charts are not designed by the nyt graphics staff.

@Tom: I think the "sufficiency" guideline was mentioned here because the graphic already contains a table with all the data -- the bubbles add no information.

The table vs. graphic question should take into account the reason you're creating the thing to begin with. If what you want to do is provide specific numerical data for all the countries as a reference, or to facilitate detailed analysis, then a simple table is a good solution. If you're trying to tell a story or support an argument, using a graphic to represent the data and calling out a few key figures is often a better one. The extent to which this graphic achieves the latter goal is hard to determine without reading the article that it was meant to accompany. If all it was aiming for was the former, however, the bubbles should go.

emegine saglık siten superr

thanks. super site. Kaiser:

Very interesting post. The New York Times usually does a much better job than they did on this chart.

I've posted on the value of this chart and generated a dot plot alternative here .

mmm

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