Since Sunday’s election I have been in the improbable position of defending Turkish pollsters. To be clear, I have had many, many quibbles with their lack of methodological transparency and the perception of bias that causes.

Unlike other forms of public opinion or policy research, however, election polling provides a day of reckoning: you’re right or you’re wrong. It’s there for everyone to see. If you can’t get the election right, within the margin of error of your sample, no one should pay attention to your data. If you repeatedly get it right, you deserve a degree of credibility.

Here’s the thing: several Turkish pollsters were pretty damn close to getting the 7 June parliamentary election correct. And when I say “correct” I mean “correct within the appropriate margin of error in the days immediately before the election.” Therefore, their November election results which missed the mark should not be dismissed outright, especially since multiple pollsters reported similar results.

I’m going to digress a bit. It’s absolutely fundamental to understand the basic principles of probability sampling if you’re going to comment on pollsters’ performance.

A poll reflects voters’ views on the days the survey was conducted within a margin of error. Here’s what that means: if you draw a truly random sample of, let’s say, n=1000 people within a universe (Turkey, for example), and you write the questions and implement the survey in ways that diminishes biases inherent in survey research and your sample reflects the demographics of your universe, your data will, within a standard margin of error of plus or minus 3.1 percentage points (characterized, shorthand, as MoE +/- 3), reflect the views of that universe on that day. That means the results of any data point could vary three points higher or three points lower. This is critical to take into consideration when declaring a poll “right” or “wrong” relative to election results or stating a candidate/party “is ahead in the polls.”

Two important takeaways:

• The only way to achieve a margin of error of zero is to interview every single person in the universe (Turkey, for example). That’s impossible and is why we rely on probability sampling. The trade-off is we have to accept and accommodate the margin of error in our analysis. If we fail to do that, we’re wrong. Period.

• Pre-election polls are not designed to project what will happen on election day (you can do that through modeling, but it’s risky). This is why everyone (especially candidates who are about to lose) says the only poll that matters is the one on election day — it’s the only one that’s a 100% accurate report of voters’ views with no margin of error.

If you don’t believe all this, go take a statistics class and then we’ll argue about it. It’s science, not magic. Also, please do not give me an exegesis on academic research. Like these pollsters, I work in the real world with budgets and time constraints.

So, let’s look at the last three public polls taken before the 7 June election. I chose these three because 1) fieldwork was conducted the week or two before the election and 2) they shared their sample sizes so we know the margin of error. (There may be others, but I found these data here). We want to look at polls conducted as close as possible to the election because they’ll capture the effects of late-breaking campaign dynamics. (Also, not rounding is an affectation. I round. Personal opinion).

 

AKP

CHP

MHP

HDP

Sample Size

MOE

Date

MAK

44

25

16

19

n=2155

+/- 2.1

18-26 May

SONAR

41

26

18

10

n=3000

+/-1.8

25 May

Gezici

39

29

17

12

n=4860

+/-1.4

23-24 May

Andy Ar

42

26

16

11

n=4166

+/- 1.5

21-24 May

June Results

41

25

17

13

n/a

0

7 June

I draw two conclusions.

First, putting aside ORC which overrepresented AKP and underrepresented HDP, Konda and Gezici were pretty damn close to the final result (by that I mean close to within the MoE), considering data was collected a week before election day.

Secondly, though it can be risky to compare data collected by different operations, their data are very similar, which suggests they are using similar methodology and making similar assumptions. That’s the way it should be.

Next, let’s look at publicly released data for the November election. I borrowed most of these data from the delightful James in Turkey and he did not always include the margin of error. I will take that up with him at a future date. Let’s assume pollsters without sample size indicated interviewed between n=3000 and n=5000 (that’s what they did in June), so the margin of error will be between +/-1 and +/-2

AKP

CHP

MHP

HDP

Sample Size

MOE

Date

Andy R

44

27

14

13

n=2400

+/-2

24-29 Oct

Konda

42

28

14

14

n=2900

+/1.8

24-25 Oct

A&G

47

25

14

12

n=4536

+/1.4

24-25 Oct

Metropoll

43

26

14

13

n=

15 Oct

Gezici

43

26

15

12

n=

15 Oct

ORC

43

27

14

12

n=

15 Oct

AKAM

40

28

14

14

n=

15 Oct

Konsensus

43

29

13

12

n=

15 Oct

Unofficial Final

49

25

12

11

N/A

+/-0

1 November

AKP’s final number falls outside all the polls’ MoE, except A&G’s. The next closest, Andy R, conducted the latest fieldwork so was in the best position to capture emerging trends, such as a surge in AKP support. Andy R still underreported AKP support by five percentage points. That’s a lot. A&G didn’t release any tracking data so it’s hard to know if it’s an outlier or ahead of the others in capturing the AKP surge. The latter is possible and I will address it in a future post.

If consistent sampling methodologies and questions are used, it’s possible track data over time to see if it changes. Big unexplainable differences from one dataset to another could indicate a problem in the methodology. I like it when pollsters provide election tracking data. It suggests sound sampling and alerts us to important trends in public opinion.

For fun, let’s take a look at two of those who did:

KONDA

AKP

CHP

MHP

HDP

June 7 Results

41

25

17

13

Aug 8-9

44

26

15

13

5-6 Sept

42

25

16

12

3-4 Oct

41

29

15

12

17-18 Oct

42

28

15

13

24-25 Oct

42

28

14

14

Unofficial November Final

49

25

12

11

GEZICI

AKP

CHP

MHP

HDP

June 7 Results

41

25

17

13

3-4 Oct

41

28

17

14

17-18 Oct

41

27

16

13

24-25 Oct

43

26

15

12

Unofficial November Final

49

25

12

11

Not only are these two pollsters consistent over time, they are also consistent with the final June results and compare favorably with each other. Nothing in either of their datasets suggests a big shift in opinion toward AKP (they do indicate an AKP trend, which is plausible). Yet, inthe end, their last polls are wrong wrong wrong about the November result. That’s really troubling.

How could pollsters who nailed it in June have missed it in November? How can they be consistent over time and with each other and be wrong on election day? Falling back on “the polls are wrong” as analysis is simply inadequate. If you’re going to disregard months of consistent data, you should provide an explanation for how it went wrong.

I honestly can’t give an adequate explanation. Because I have other things to do and you have short attention spans when it comes to statistics, I will address what I think are the three most likely polling error culprits in future posts. These include (in random order of in likelihood):

• Errors in methodology (this will address the absurd argument that since UK and US pollsters were wrong, it follows that polls in Turkey are also wrong. I can’t believe this is even necessary)

• Errors in analysis (not reporting or considering Undecideds or softening support, which is my current theory of choice)

Election dynamics that cannot be captured by polling

NOTES: If you want to look at a few other pollsters’ June data, here it is. I don’t think it’s totally fair to judge their accuracy based on data collected weeks before election day, but, with the exception of under-representing HDP, most of them (except MAK) actually are pretty close and provide more evidence of the consistency of public opinion. Being off on HDP can be forgiven because HDP had what campaign people refer to momentum and it is plausible HDP’s support increased in the final weeks.

AKP

CHP

MHP

HDP

Sample Size

MOE

Date

MAK

44

25

16

19

n=2155

+/- 2.1

18-26 May

SONAR

41

26

18

10

n=3000

+/- 1.8

25 May

Gezici

39

29

17

12

n=4860

+/- 1.4

23–24 May

Andy Ar

42

26

16

11

n=4166

+/- 1.5

21-24 May

June Results

41

25

17

13

N/A

0

7 June

Here we are again, weeks out from another Turkish election, arguing on Twitter and in bars about the pre-election polls on the Presidential race between the shouty guy and the bread guy. As much as we’d like to, we can’t really ignore this election, so wouldn’t it be great if someone explained how to tell if a poll in the paper is credible or not?

It’s your lucky day! Here are some basic, but important, concepts to understand before you write about, argue about, print, or tweet publicly released election polls (everywhere, too, not just Turkey).

 

  • How many people were interviewed? It amazes me how few press articles include this mandatory information. A nationally representative sample should include at least 800 randomly selected respondents, which has a margin of error (MOE) of 3.5% at the 95% level of confidence.* A larger sample size does not necessarily mean the survey is better (academics may argue otherwise, but their research goals are different), so don’t fall into that trap. For example, the margin of error for a n=2000 sample is 2.2% (compared to 3.5% for n=800). That’s not a big difference and won’t matter that much except in the closest elections. However, if the pollster is sharing data from smaller demographic or geographic subgroups within the national sample (men, women, Kurds or Istanbullus, for example), a larger sample size becomes more important. Remember, the MOE increases as the number of interviews decrease. If Istanbul makes up 19% of the country (and in a nationally representative sample, it will) in an n=800 sample, there will be only 152 interviews among Istanbullus, with a MOE of 8%. If the sample is n=2000, there will be 380 interviews (MOE 5%) among Istanbullus. I’m slightly more comfortable with the latter data than the former because the margin of error is smaller. Do you like to play around with sample sizes? I do! There’s an app for that.
  • Who paid for it?  This is Turkey so this is probably the single most important question. In the US, major media outlets (and think tanks) commission credible research firms to conduct election surveys (the “CNN/Washington Post poll,” for example), the results of which papers report as news. Given they are in the business of reporting things that are more or less true, they have a lot at stake by getting the numbers right. The media in Turkey operate according to different principles. That a media outlet reports data tells us little more than in whose favor the numbers are likely to have been cooked. Methodologically sound research is expensive in Turkey — $20,000 to $30,000 for data collection alone — and for-profit research firms are unlikely to undertake survey work for fun, even if they say they do. Someone’s paying for it and if you can’t find out who, don’t report it.

 

  • Who was interviewed? Election polls are designed to predict election outcomes. It sounds harsh, but non-voters’ opinions don’t matter. Therefore, only likely voters should be polled. Because voting is compulsory in Turkey, election participation is very high (88%-90%) so nearly all adults are eligible to participate in an election survey. In contrast, election polling in the US is extremely complicated: only about 50% of Americans are eligible to vote (by virtue of having registered), and among those, participation rates vary from the extremely low (15% in low-interest primaries) to the less low (about 65% in presidential elections). Predicting who should be included in a sample of likely voters is extremely challenging. Misreading the composition of the electorate was one of the reasons major polling firms got the US election in 2012 wrong. Because of its timing (10 August, mid-vacation), uniqueness (it’s the first time Turkish voters have directly elected a president) and low interest in the candidates among the tatıl-class, Turkey’s presidential election presents a unique challenge to election pollsters. Is there going to be substantial drop-off in participation among certain types of voters who won’t bother to return to Istanbul from Bodrum’s beaches to vote? Maybe! Pollsters who care about accuracy will take this into account. They should explain how they’re addressing this issue, and how, if at all, they’re diminishing their samples to exclude those who won’t vote. Ask! Ask! Ask!

 

  • How did they conduct the interviews? Generally, in probability samples (the only kind that produces representative data and the only kind I will discuss), a respondent is selected at random to participate in either a face-to-face (F2F) or telephone interview. F2F has always been the norm in Turkey because of low phone penetration but that’s changing quickly as more and more people obtain mobile phones. Mobile sampling is becoming more and more common. Both methodologies have biases and you should know which methodology the pollster uses so you can be aware of them. I can go on for days about the pros and cons of each (it’s a wonder I have any friends at all). Online, web-only surveys are bogus. If you ever want to start a flame war with me on Twitter, report on an online survey like this one without using the word “worthless.”
  • What’s the polling firm’s track record? Accuracy is a pollster’s currency. The great thing about election polling is there’s a day of reckoning. You either get it right and can be smug (it’s science!) or you’re wrong and no one should listen to you anymore. Given the dearth of credible election polls in Turkey, calling previous election results correctly boosts a pollster’s credibility even more in my book. As far as I know, and I don’t know everything, one firm did that publicly in the March local elections: Konda. Why data released by firms that got a recent election completely wrong are treated as credible is a mystery to me. It’s easy to check.

 

This isn’t all there is, but it’s plenty and you don’t have to be a specialist to interpret it (as long as you understand probability sampling). Having the answers to these questions will make it easier to assess the quality of the polls you see in the Turkish press and on Twitter. Armed with this information, you’ll have the tools to be able to say “this poll sounds like BS. I’m not going to report/tweet it,” thus depriving bogus pollsters of the media oxygen they need to survive. If you can’t get answers to these questions, don’t report the data.

 

TOMORROW (or some day in the near future)! How to Make Public Election Polling in Turkey More Credible 

 

*If your universe (total number of potential respondents) is greater than a couple hundred people, the margin of error is the same for a random sample of n=800, regardless if you’re surveying a city with a population of 1500 people or a country of 78 million. If you don’t understand why this is, or what a margin of error is, get thee to a Stats 101 course and don’t start arguments you’re going to lose.

**Quirk Global Strategies isn’t in the business of public polling (or academic research). We’re strategic pollsters, which means private clients use our data to guide their internal political or communications strategies (though not in Turkey). This is an important distinction. Strategic pollsters who collect bogus numbers give bad advice, lose elections and don’t get hired again. Therefore, we strongly oppose BS numbers. You can be certain that strategic polling is being done in Turkey — most likely on behalf of AKP — but you and the twitter loudmouths you follow are unlikely to get your hands on it.

 

Like many of you, I have visited Gezi Park over the last few days. While walking around, I noticed that a lot of the protesters are young and they seem new to the business of protesting. They had strongly held views on a lot of topics but are not overtly political.

My observation is about as scientifically valid as the poll released by Bilgi University earlier this week. I’m not going to repeat the findings. That so many respected journalists are citing and retweeting it without mentioning (or probably even looking to see) that, according to the exceedingly vague methodology statement, it’s a 20 hour online survey of 3000 people, is vexing. I’m going to assume (probably incorrectly, but I’m struggling to be generous) that there’s more information about the methodology in the Turkish, but when I saw the word “online” that’s when I clicked “close tab.”

Polling 101: Online surveys are representative of nothing except the universe of people who 1) knew about it, 2) had internet access during the 20 hours it was open, 3) felt like responding.  Participants were not randomly selected; they choose to participate, which makes them different at least one way from those who did not. It’s called selection bias.

Even worse, it appears that a lot of folks are repeating data from the poll because “it seems to make sense.” That’s confirmation bias, which is also sloppy.

If you really have to cite that poll, I suggest phrasing it thusly, “According to a worthless online survey of Gezi Park protesters publicly released by Bilgi University, which you’d think, as an academic institution would know better……”

There are ways to randomly select a sample of protesters and find out more about their demographics and attitudes. It’s time consuming and expensive, like good research usually is. Wait until someone does that, then report it.

I have something to say approximately every four years. I’m like a pollster cicada.