To show how important units are in our communication concerning statistics please read the following (which is an excerpt from Delancyplace.) In today's selection - people often mistrust statistics under the presumption that statistics can easily be manipulated. And they can. Particularly for those uncomfortable with numbers or unwilling to dig into the issue. (Samuel Clemens is often noted for having said "lies, damned lies, and statistics," which he in turn attributed to British Prime Minister Benjamin Disraeli). One form of manipulation is changing the unit of analysis, as in the two examples below: "Is globalization making income inequality around the planet better or worse? By one interpretation, globalization has merely exacerbated existing income inequalities; richer countries in 1980 (as measured by GDP per capita) tended to grow faster between 1980 and 2000 than poorer countries. The rich countries just got richer, suggesting that trade, outsourcing, foreign investment, and the other components of 'globalization' are merely tools for the developed world to extend its economic hegemony. Down with globalization! Down with globalization! "But hold on a moment. The same data can (and should) be inter¬preted entirely differently if one changes the unit of analysis. We don't care about poor countries; we care about poor people. And a high proportion of the world's poor people happen to live in China and India. Both coun¬tries are huge (with a population over a billion); each was relatively poor in 1980. Not only have China and India grown rapidly over the past sev¬eral decades, but they have done so in large part because of their increased economic integration with the rest of the world. They are 'rapid global¬izers,' as the Economist has described them. Given that our goal is to ameliorate human misery, it makes no sense to give China (population 1.3 billion) the same weight as Mauritius (population 1.3 million) when examining the effects of globalization on the poor. The unit of analysis should be people, not countries. What really happened between 1980 and 2000 is [that] ... the bulk of the world's poor happened to live in two giant countries that grew extremely fast as they became more integrated into the global economy. The proper analysis yields an entirely different conclusion about the benefits of globalization for the world's poor. As the Economist points out, 'If you consider people, not countries, global inequality is falling rapidly.' "The telecommunications companies AT&T and Verizon have recently engaged in an advertising battle that exploits this kind of ambiguity about what is being described. Both companies provide cellular phone service. One of the primary concerns of most cell phone users is the quality of the service in places where they are likely to make or receive phone calls. Thus, a logical point of comparison between the two firms is the size and quality of their networks. While consumers just want decent cell phone service in lots of places, both AT&T and Verizon have come up with different metrics for measuring the somewhat amor¬phous demand for 'decent cell phone service in lots of places.' Verizon launched an aggressive advertising campaign touting the geographic cov¬erage of its network; you may remember the maps of the United States that showed the large percentage of the country covered by the Verizon network compared with the relatively paltry geographic coverage of the AT&T network. The unit of analysis chosen by Verizon is geographic area covered -- because the company has more of it. "AT&T countered by launching a campaign that changed the unit of analysis. Its billboards advertised that 'AT&T covers 97 percent of Americans.' Note the use of the word 'Americans' rather than 'America.' AT&T focused on the fact that most people don't live in rural Montana or the Arizona desert. Since the population is not evenly distributed across the physical geography of the United States, the key to good cell service (the campaign argued implicitly) is having a network in place where callers actually live and work, not necessarily where they go camp¬ing. As someone who spends a fair bit of time in rural New Hampshire, however, my sympathies are with Verizon on this one."
Author: Charles Wheelan Title: Naked Statistics Publisher: W.W. Norton & Company Date: Copyright 2013 by Charles Wheelan Pages: 41-42 Naked Statistics: Stripping the Dread from the Data by Charles Wheelan by W. W. Norton & Company