The first thing we know about kitchen cabinets is that they are not large enough. If you live in a small city apartment, you're always looking for ways to maximize your space. If your McMansion has a huge kitchen, you'll run out of space all the same, after splurging on the breadmaker, and the ice-cream maker, and the panini grill, and containers for garlic, onions, different shapes of pastas, and the peelers for apples, garlic, carrots, the egg-separator, the foam-maker, and so on.
Another thing we know is that no matter how many and how large the cabinets are, there is not enough premium space, by which we mean front-facing space within arm's reach. What has this to do with graphs and charts? We'll find out soon enough.
In this weekend's edition of New York Times (link 1, link 2), several climate scientists wrote about droughts in America: "widespread annual droughts, once a rare calamity, have become more frequent and are set to become the 'new normal'". What caught my eye was the following graphic showing precipitation levels, enticingly titled "21 Centuries of Rainfall in New Mexico". (See the full graphic here).
The blue lines going up represent years in which rainfall was higher than normal; the orange lines going down show years of below-normal rainfall. "Normal" is defined as the average rainfall between 1931 and 1990. Particularly useful were the annotations telling us in certain centuries, the number of years below normal.
I immediately needed to see the following chart:
This just takes the annotations and plotted them directly (I made up the data where they were not noted.)
What we are seeing here, at the scale of centuries, is that in the most recent period (only up to 1992), New Mexico is getting wetter.
Yes, this chart doesn't seem to support the scientists' assertion. In fact, I'm not sure why the NYT decided to insert this "news analysis" next to the opinion column. It's not that the analyst doesn't see the contradiction - he stated "the bigger picture, from El Malpais, suggests that the West has endured far drier periods. Uncomfortably drier."
I have major issues with this juxtaposition. If the NYT does not think the opinion column is correct science, it should decide not to print it. If the NYT thinks there are people who might object to the science, it should counter it by citing the work of other scientists (none is cited in the sidebar). While El Malpais may provide the longest measure of rainfall conditions, this is no basis to claim it measures "the bigger picture", and specifically it is shocking, perhaps reflecting the cultural bias of the newspaper, to see that this data from New Mexico tell us something about "the West" and somehow not about "the East". Why would it generalize to the West but not the East?
Back to the chart, and specifically kitchen cabinets.
We have two charts from one data set. The chart of blue and orange spikes contains every data point. The stacked column chart shows only aggregated data, specifically how many above-average and below-average years in each century. The first chart makes readers work very hard to get any information out of it. The designer recognizes this and adds useful notes, generally about the proportion of below-average years. Assuming that those proportions are the key to deciphering the chart, why not plot them directly?
The objection is that much information is lost by not including the rest of the data. One cannot deny it. For example, just looking at the stacked column chart, you cannot know that the late 1980s and early 1990s were extremely wet years in New Mexico, over three standard deviations above the norm, nor can you know that there was a mega-drought in the late 16th century lasting decades.
However, chart designers should realize that there is a shortage of front-facing, accessible space in the kitchen cabinets. Putting more into a chart means some of the information will be pushed to the back, or out of arm's reach. If you need a ladder to get to that cabinet, what would you put in it? Would you rather leave it empty? I know I would.