Posted on 10/21/2003 12:23:07 AM PDT by Wolfstar
Ah, the omnipresent poll. The media punditocracy is addicted to using polls to tell us what "the American people feel" (never think) about everything from a president's so-called approval rating, to how a candidate's chances stack up against others in a race, to our "feelings" about various policy and social issues. Although the public has absolutely no way to evaluate the vast majority of polls for accuracy, most of us simply accept them as incontrovertible indicators of truth. Why? The answer probably is because we're told that polls are "scientific" since they use statistical-type analysis, and most of us tend to equate science with a search for objective truth.
Despite the scientific patina of a Margin of Error, how does one incontrovertibly prove a poll to be accurate? For nearly all polls, the answer is that it can't be done. In the political realm, only polls taken closest to an election can be compared for accuracy to the actual results of real voters expressing their real attitudes at the ballot box.
Nevertheless, the public is conditioned not to look too closely at the accuracy of polls. We're told polls are "just a snapshot in time." So we learn to shrug when there are big swings in, say, a president's "approval ratings" from one month to the next even though nothing particularly new happened during that time. Despite the fact that only a handful of polls close to elections can be verified against objective results of real votes, polls affect our society in several ways. The worst is that many politicians, hanging on their every nuance, too often make crucial policy decisions based on polls wielded like clubs by the media and special-interest groups.
So what's the truth about polls? Few in the public have the time or resources to do an in-depth study in an attempt to answer that question, while those who butter their bread on the back of polls have no incentive to do so. Ah, but fate stepped in this year in the form of the California Recall and provided an excellent opportunity to do a case study of multiple polls taken in a highly compressed period of time. Since all poll results in this study were obtained relatively close to Election Day, a comparison to actual election results is not only easier, but also more instructive than, say, an apples-to-oranges comparison of a year's worth of "approval ratings" to an election outcome.
This study encompasses 20 polls taken by nine polling organizations between Aug. 7 and Oct. 5, 2003. It looks at the five most-watched poll questions those which purported to measure the percent of vote for:
Because there are 20 polls and five questions, this study encompasses 100 individual results. When analyzed by several criteria, such as poll date and accuracy for each of the five questions, an eye-popping picture of polling precision or lack thereof comes into sharp focus. Note that "accurate" in this study means: (1) a poll result within that poll's MOE, and (2) as compared to the actual election results. "Inaccurate" or "wrong" means a poll result outside that poll's MOE as compared to the actuals.
Q: Are political polls accurate?
A: Based on this study, the answer is: While some results for some questions in a multi-query poll may be accurate, most polls, when taken in their entirety, are not. Here's why: Of the 100 individual question results, more than half (57) were wrong (outside their MOE's), as compared to the actual election results.
However, the stunning fact is that only 1 poll in 20 gave accurate results across-the-board for all five questions. This was the last poll taken by Survey USA from Oct. 3-5. Only 4 of 20 got both the Yes and No on recall questions right, while only that last Survey USA poll gave accurate Candidate results. In other words:
Looking at accuracy another way, of the 100 individual question results, less than half (43) were right within their poll MOE's. Most (67) under-estimated the actual election results, and only seven poll questions called that election result precisely.
Q: Does averaging several polls over a period of time give a more accurate picture?
A: Some pollsters, reporters and others who rely on them believe either a tracking poll, or an average of several polls taken over a period of time, are the best methods of obtaining an accurate picture of public attitudes. Due to the compressed two-month recall campaign, all 20 polls, taken together, constitute a form of tracking poll. Yet, as already noted, their often wildly inaccurate results only contributed to a false week-to-week perception of the race. So would averaging the results of all 20 polls give a more accurate picture? The answer based on this study is a qualified yes. Here's why. First, all 20 MOE's were averaged to establish a baseline, which works out to ±3.6%.
Q: Is the Margin of Error (MOE) really useful in assessing a poll's accuracy?
A: Based on this study, the answer is a resounding NO! The smallest MOE given was ±2%; the largest ±5.6%. Interestingly, ±2% was for one of the earliest, most inaccurate polls, while ±5.6% was for the last and most accurate.
Q: Do polls become more accurate closer to an election?
A: The broad answer is a qualified yes qualified because, in this study, the polls were inconsistent on this question. Results for some questions in early polls were quite accurate, while some late poll results were very inaccurate. However, the trend was to become more accurate closer to the election.
As already noted, the last poll was the only one that got all five questions right within its MOE. The following table shows the total poll questions that the first/last seven polls got right within each poll's MOE. An accuracy of 100% in this instance would be 35 questions right (7 polls x 5 questions). Note that just under twice as many question results were right in late polls than in early ones. Nevertheless, even the late polls (last two weeks) got less than half (49%) of the questions right.
First 7 polls (8/8 to 9/8)
|
x
|
Last 7 polls (9/24 to 10/5)
|
||
Question |
# Poll Questions |
x |
Question |
# Poll Questions |
YES |
2
|
x |
YES |
5 |
NO |
1 |
x |
NO |
2
|
AS |
0 |
x |
AS |
1 |
CB |
1 |
x |
CB |
4 |
TC |
5 |
x |
TC |
5 |
TOTAL |
9 (26%) |
x |
TOTAL |
17 (49%) |
Q: Are political polls biased?
A: If any given poll is biased, the hard question to answer is whether or not it is due to ideology or methodology. Every expert on polling says that variables such as the way a question is worded; who the respondents are; the order of questions; even what time of day/week a poll is taken can create a bias. (Many polling organizations do not make their methodology public.) As the following demonstrates, an argument can be made either way for these California recall polls:
So are political polls biased? Whatever the answer, the staggeringly inaccurate polling for Schwarzenegger and moderately inaccurate results for Bustamante as compared to the surprisingly accurate, even slightly inflated results for McClintock certainly should raise a lot of eyebrows. Of the five poll questions in this study, results for Arnold Schwarzenegger were by far the most inaccurate, while those for Tom McClintock were the most accurate. Was there really a mid-to-late September surge for McClintock? Or, as many suspected, were the polling organizations trying to inflate impressions of his strength as compared to that for Schwarzenegger? And did the polls underestimate Bustamante's vote strength in order to boost Gray Davis? One would be tempted to say "yes" to these questions were it not for the fact that 90% of the polls also underestimated the No on recall vote.
Q: Which polling organization was the most accurate?
A: The following table speaks for itself, although the reader is encouraged to take particular note of the poor performance of two big national polls, Time/CNN and Gallup.
Polling Organization |
# of Polls |
Total # of Results |
# of Correct |
Percent |
Knight Ridder |
1 |
5 |
3 |
60% |
Los Angeles Times |
3 |
15 |
9 |
60% |
Survey USA |
5 |
25 |
13 |
52% |
CA Chbr of Commerce |
2 |
10 |
5 |
50% |
Field Poll |
3 |
15 |
7 |
47% |
Time/CNN |
1 |
5 |
2
|
40% |
Public Policy Institute |
2 |
10 |
3 |
30% |
Gallup |
2 |
10 |
1 |
10% |
Stanford U. |
1 |
5 |
0 |
0% |
Q: What conclusions can be drawn from this study?
A: Even the most accurate polls in this study were wrong 40% of the time overall (based on above accuracy table). The accuracy of each of their internals was worse. So, when the national media tout polls from Gallup, Time/CNN, Newsweek, Zogby, and such about what "the American people feel" regarding something insubstantial like "presidential approval;" or whether or not they want to re-elect the president; or which issues are most important to them; or how a person who's name is all but unknown nationally suddenly becomes "the frontrunner" for a party's nomination, it's wise to keep three things in mind:
Notes for Tables of Results:
YES/NO Table Of Results:
Final Results |
|
55% |
|
|
45% |
|
|
|
Poll |
Date |
YES |
+Over |
Within MOE |
NO |
+Over |
Within MOE |
MOE |
Survey USA |
Oct. 35 |
57% |
+2 |
Y |
43% |
-2 |
Y |
±5.6% |
Knight Ridder |
Oct. 14 |
54% |
-1 |
Y |
41% |
-4 |
N |
±3% |
Field Poll |
Sep. 29Oct. 1 |
57% |
+2 |
Y |
39% |
-6 |
N |
±4.8% |
Survey USA |
Sep. 2830 |
61% |
+6 |
N |
39% |
-6 |
N |
±3.7% |
Los Angeles Times |
Sep. 2529 |
56% |
+1 |
Y |
42% |
-3 |
Y |
±3% |
Gallup |
Sep. 2527 |
63% |
+8 |
N |
35% |
-10 |
N |
±3% |
CA Chbr of Commerce |
Sep. 2425 |
53% |
-2 |
Y |
41% |
-4 |
N |
±3.5% |
Survey USA |
Sep. 1922 |
57% |
+2 |
Y |
42% |
-3 |
Y |
±3.5% |
Public Policy Institute |
Sep. 817 |
53% |
-2 |
Y |
42% |
-3 |
Y |
±3% |
Los Angeles Times |
Sep. 610 |
50% |
-5 |
N |
47% |
+2 |
Y |
±3% |
Survey USA |
Sep. 68 |
62% |
+7 |
N |
37% |
-8 |
N |
±3.7% |
Field Poll |
Sep. 47 |
55% |
exact |
Y |
40% |
-5 |
N |
±4.5% |
CA Chbr of Commerce |
Sep. 14 |
52% |
-3 |
Y |
41% |
-4 |
N |
±3.1% |
Stanford U. |
Aug. 29Sep.8 |
62% |
+7 |
N |
38% |
-7 |
N |
±3.4% |
Survey USA |
Aug. 2325 |
64% |
+9 |
N |
35% |
-10 |
N |
±3.7% |
Los Angeles Times |
Aug. 1621 |
50% |
-5 |
N |
45% |
exact |
Y |
±3% |
Field Poll |
Aug. 1013 |
58% |
+3 |
Y |
37% |
-8 |
N |
±5% |
Public Policy Institute |
Aug. 817 |
58% |
+3 |
N |
36% |
-9 |
N |
±2% |
Time/CNN |
Aug. 8 |
54% |
-1 |
Y |
35% |
-10 |
N |
±4.3% |
Gallup |
Aug. 710 |
69% |
+14 |
N |
26% |
-19 |
N |
±4% |
Average of 20 polls |
|
57% |
+2 |
Y |
39% |
-6 |
N |
3.6% |
# Results within MOE |
|
|
|
11 |
|
|
6 |
|
# Results outside MOE |
|
|
|
9 |
|
|
14 |
|
# Same as actual |
|
|
1 |
|
|
1 |
|
|
# Over actual |
|
|
12 |
|
|
1 |
|
|
# Under actual |
|
|
7 |
|
|
18 |
|
|
CANDIDATE Table Of Results:
Final Results |
|
49% |
|
|
32% |
|
|
13% |
|
|
|
Poll |
Date |
Arnold S. |
AS +Over |
Within MOE |
Bustamante |
CB +Over |
Within MOE |
McClintock |
TM +Over |
Within MOE |
MOE |
Survey USA |
Oct. 35 |
46% |
-3 |
Y |
34% |
+2 |
Y |
13% |
exact |
Y |
±5.6% |
Knight Ridder |
Oct. 14 |
37% |
-12 |
N |
29% |
-3 |
Y |
15% |
+2 |
Y |
±3% |
Field Poll |
Sep. 29Oct. 1 |
36% |
-13 |
N |
26% |
-6 |
N |
16% |
+3 |
Y |
±4.8% |
Survey USA |
Sep. 2830 |
45% |
-4 |
N |
28% |
-4 |
N |
16% |
+3 |
Y |
±3.7% |
Los Angeles Times |
Sep. 2529 |
40% |
-9 |
N |
32% |
exact |
Y |
15% |
+2 |
Y |
±3% |
Gallup |
Sep. 2527 |
40% |
-9 |
N |
25% |
-7 |
N |
18% |
+5 |
N |
±3% |
CA Chbr of Commerce |
Sep. 2425 |
35% |
-14 |
N |
31% |
-1 |
Y |
17% |
+4 |
N |
±3.5% |
Survey USA |
Sep. 1922 |
39% |
-10 |
N |
32% |
exact |
Y |
18% |
+5 |
N |
±3.5% |
Public Policy Institute |
Sep. 817 |
26% |
-23 |
N |
28% |
-4 |
N |
14% |
+1 |
Y |
±3% |
Los Angeles Times |
Sep. 610 |
25% |
-24 |
N |
30% |
-2 |
Y |
18% |
+5 |
N |
±3% |
Survey USA |
Sep. 68 |
39% |
-10 |
N |
29% |
-3 |
Y |
16% |
+3 |
Y |
±3.7% |
Field Poll |
Sep. 47 |
25% |
-24 |
N |
30% |
-2 |
Y |
13% |
exact |
Y |
±4.5% |
CA Chbr of Commerce |
Sep. 14 |
28% |
-21 |
N |
33% |
+1 |
Y |
12% |
-1 |
Y |
±3.1% |
Stanford U. |
Aug. 29Sep. 8 |
40% |
-9 |
N |
28% |
-4 |
N |
8% |
-5 |
N |
±3.4% |
Survey USA |
Aug. 2325 |
45% |
-4 |
N |
29% |
-3 |
Y |
11% |
-2 |
Y |
±3.7% |
Los Angeles Times |
Aug. 1621 |
22% |
-27 |
N |
35% |
+3 |
Y |
12% |
-1 |
Y |
±3% |
Field Poll |
Aug. 1013 |
22% |
-27 |
N |
25% |
-7 |
N |
9% |
-4 |
Y |
±5% |
Public Policy Institute |
Aug. 817 |
23% |
-26 |
N |
18% |
-14 |
N |
5% |
-8 |
N |
±2% |
Time/CNN |
Aug. 8 |
25% |
-24 |
N |
15% |
-17 |
N |
9% |
-4 |
Y |
±4.3% |
Gallup |
Aug. 710 |
42% |
-7 |
N |
22% |
-10 |
N |
13% |
exact |
Y |
±4% |
Average of 20 polls |
|
34% |
-15 |
N |
28% |
-4 |
N |
13% |
exact |
Y |
3.6% |
# Results within MOE |
|
|
|
1 |
|
|
11 |
|
|
14 |
|
# Results outside MOE |
|
|
|
19 |
|
|
9 |
|
|
6 |
|
# Same as actual |
|
|
0 |
|
|
2 |
|
|
3 |
|
|
# Over actual |
|
|
0 |
|
|
3 |
|
|
10 |
|
|
# Under actual |
|
|
20 |
|
|
15 |
|
|
7 |
|
|
Not to defend the pollsters, but if they didn't get the pre-election surveys right, why would the get the post-election surveys right?
(Actually, I guess that's not exactly a defense of the pollsters' abilities at all, is it? Hee hee.)
I'm also a total believer in the average person's inability to remember how they felt on an issue one week in the past compared to today, much less a month ago or more. Lots of people rationalize outcomes in their own minds after the fact.
For a more in-depth answer to your query, look at the question: Do polls become more accurate closer to an election? The answer is that, in this study, they trended toward more accuracy closer to the election, but not strongly. Even at the end, only one poll got all five questions right within it's MOE.
I'm not trying to be a critic here, and I totally appreciate your efforts. However, I am almost positive that, for example, a MOE of 5% means something like "there is a 90% chance that the actual results will lie within +/-5% of the poll results." Anyway, something to think about.
If someone analyzed the actual error (instead of categorizing right/wrong), the LAT probably would not be in the top two, since their Schwarzenegger predictions were very far from the actual results.
Thanks for summarizing the results and sharing with us all!
Some of the polls stated something like that, but the newspapers or TV news charts often simply say the MOE was 5%, and it's often left out entirely in oral TV/radio news.
Maybe they couldn't predict the dynamics of the actual voters this time, because voters were motivated in ways not typical of the usual elections. If they had realized this, the polls should have claimed an 80% or lower accuracy.
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