The trend in opinion on health care reform has been a bit tricky of late. After a long and substantial rise of opposition, and an equally long but less sizable decline in support, we came to August, the month for the strange in politics. This year was stranger than most with loud and angry town halls, fearful politicians reluctant to meet constituents, cable news of gun toting demonstrators, an extended presidential vacation and the death of an icon. And what did all the rancor produce? Apparently, the sound and fury signified, surprisingly, a flattening of the trends in opinion. Opposition slowed its rise (not accelerated), and support halted its fall and by the second week of August, began a modest rise. And that before the president spoke to the joint session of Congress.
The picture is complex in the details, but essentially unanimous in the major points. Let me lay the details out a bit.
The chart above shows all the trend lines we might estimate for our health care questions, using 65 different levels of sensitivity for the smoothing. At one end, we smooth little and get a very (overly) sensitive fit. At the opposite end we smooth a lot and get a quite insensitive trend. In between is our standard estimator. The overlapping lines above make clear that the big picture is a common pattern over all 65 different degrees of sensitivity: A rise, then a flattening of opposition, and a smaller fall then a rise in support. Off to the right, you can see "bar codes" showing all the different possible current trend estimates from each of the 65 different levels of smoothing. The range of possible current trends is small, but there is a little overlap indicating some estimates may show support slightly ahead of opposition, though most show the opposite.
If you want to pick a fight, then you can pick a level of smoothing that is a little different from the others in some details. The chart below is the most sensitive estimator, one that is quite likely to chase noise, but which also picks up short term changes.
Now you can see a post-speech spike in support, and a smaller drop in opposition. Both are sharp, but both also show the beginnings of a reversion in the latest polls, with support beginning to dip and opposition steady or slightly rising. If you believe this estimator, then the speech mattered, but wasn't a game changer because the short term gain for Obama has now begun to reverse.
Or, you could use a still sensitive but not quite so erratic estimator:
And, Aha! the speech changed everything and the trend is now declining opposition and rising support! Well, maybe. But this rests on being sensitive enough to pick up the speech effect, but not so sensitive as to turn down based on those very latest polls.
Or you could use our standard estimator, which is "sensitive enough" but which tries not to chase outliers. It needs several polls to convince it that the polling trend has really changed.
Here we see an upturn, probably driven by the speech, but the blue line hasn't caught the red line yet.
If you compare the red line in the chart above, with the red line in our interactive chart today, you'll see a bug. For reasons not yet clear, the interactive chart is producing a straight line for the opposition trend despite the fact that our standard estimator is really the red line above. Mark mentioned this mysterious bug in a previous post here. We continue to hunt it and hope for a quick fix. (For the really nerdy, we have to stabilize the line when few polls are available, and sometimes it seems the "stabilizers" kick in when they shouldn't. Probably due to the very first poll which is far from the rest. Take it out of the interactive chart with the filter option, removing HealthDay/Harris, and you get estimates much closer to the standard trend above.)
Notice that the blue line above and the corresponding black line in our interactive chart are very similar. So the interactive chart is doing the right thing with one line but not with the other. The interactive chart overshoots putting opposition at 49.9% while my estimate above is 48.5%. Meanwhile support is 45.4% on the interactive chart and 45.8% here.
Finally, what if we intentionally over-smooth-- ignoring the day-to-day noise for the long term "fundamentals" trend:
The same basic story is apparent. Opposition has grown but is now slowed to a near halt. Support reversed its decline sometime in August and has begun an upturn.
And my big point is that this is essentially the picture you see in all these different trend estimates. The details are slightly different. A bump here and a drop there, and the precise estimates of support and opposition differ by as much as 2 points up or down. But the big picture is that opposition ramped up significantly through June or July but has recently slowed or stopped. Support fell less precipitously but has been working back up for a month (despite or perhaps because of the circus coverage in August.) We could pick a chart to fight over the details, but we shouldn't. It is the big picture of public opinion that is important here. Within a couple of points, opinion is evenly divided. The White House has gained a bit of momentum, but will be challenged to lower the opposition numbers, not just raise the support numbers.
Here is a chart of how the current trend estimates depend on the degree of smoothing. The range of opposition is 47-49 and the range of support is a little wider, 45-49.
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