Archive for awful graphs

A dubious statistic

Posted in Books, R, Statistics with tags , , , on June 1, 2011 by xi'an

Following a link on R-bloggers, I ended up on this page (with a completely useless graph that only contained the pieces of information 5% in 1900 and 55% in 2000). The author (Ralph Keeney) reports on “A remarkable 55 percent of deaths for people age 15 to 64 can be attributed to decisions with readily available alternatives.” This sounded to me like a highly dubious finding… So I looked at the paper itself, reading that

“A personal decision is a situation where an individual can make a choice among two or more alternatives. This assumes that the individual recognizes that he or she has a choice and has control of this choice. Readily available alternatives are alternatives that the decision maker would have known about and could have chosen without investing much time or money.” Ralph Keeney

This categorisation of deaths is highly debatable, in that choice is not always that available! So I do not see how the author can assert which percentage of the individuals truly have control of the choice… (For instance, can people refuse doing dangerous jobs when they desperately need a job? or when the dangerousness is an abstract concept as, say, for a Fukushima worker? Is obesity a sheer matter of will?) Furthermore, the jump from 5% to 55% is also highly shaky: “Clearly, one should not put much credibility in this 22% for 1950 or the corresponding 5% for 1900″.  In the end, tt seems that the whole issue of the paper is about the amount of information: “in 1900 the knowledge about and ability to avoid many of the causes of death would seem to be much lower than in 2000″. So life has not been getting more dangerous or people sillier, simply information about the causes of deaths has become more widespread. I am thus surprised at the low level of academic input contained in the paper (look at the “life-saving decisions’!), which may actually explain for the echo it found on the blogosphere. (This post also appeared on the Statistics Forum.)

Stacking up chores, haphazardly…

Posted in Statistics with tags , on August 2, 2009 by xi'an

A fairly awful “statistical” graph appeared in the Business section of the Sunday New York Times, today. It slices the day chores of a population along the day by percentages, which means that an erratic dynamics for one activity (sport, say) impacts all activities of top. This is one problem. Another one is that we naturally react to surface representation more than to slices, so the global information of how the day is spent. Since activities are piled up, comparing two populations with respect to one single activity is almost impossible, except for sleep which is the bottom activity. This is not mentioning the side effects of how the questions were asked to the participants, how non-response was processed and so on… And the biases resulting from a raw interpretation like “On an average weekday, the unemployed sleep an hour more than their employed peers” which does not account for the difference in the categories, like the fact that people may be unemployed because they are sick and other side effects.

Follow

Get every new post delivered to your Inbox.

Join 701 other followers