This is a technical issue more than a policy issue, but it has some policy implications, in keeping with this websiteâ€™s slogan. It is prompted by so many recent polls that purport to show that Republicans seem to be backing Trump with no diminution in fervor. Many of these polls are cited by Charles Blow in his op-ed pieces in the New York Times. And todayâ€™s Washington Post-ABC poll shows a similar split between Republicans (67% support exiting the climate agreement) and Independents (22%) and Democrats (8%).
My question is, do those statistics reflect no change in Trump support, or is something else going on as well? In particular, is the percentage of people who self-identify as Republicans going down, leaving only the most fervent supporters in those retaining allegiance to the party?
I have a similar question about the data from the Energy Information Administration (EIA) posted by James Wimberly. In the EIA example, the percent of energy use is depicted over time, showing, for example, that hydropower has gone from generating 30 percent of total US electricity in 1950 to six percent in 2016.
Now it may be that some dams were decommissioned over the past sixty-odd years. I would guess, however, that itâ€™s more likely that the total amount of hydropower-generated electricity has not dropped very much, but that its share has dropped because we are using more electricity overall. A better graphic would be one that shows the actual output of each source instead of its share of the total. [And an even better graphic would be one that stacked the contributions one on top of the other, adding up to the total energy usage, which would show the actual contributions rather than the relative contributions.]