Let's do math. 45% of CNN's sample was under 50 years old

[Godhumor]

Let's break this down.

1006 respondents total. 26% Democratic. So 262 respondents were Democratic.

Sample for Democratic nomination was only registered Democrats. There were 924 registered respondents total (92%). Assume same proportion for Democrats and you get a new sample of 240 people.

Doing some basic math based on percentages given for each nominee, the lowest possible split for under 50 voters is 107 vs 133 for over 50. Math is not perfect but it is pretty close for information presented. And lo and behold a sample under 110 has a MoE over 8.5%.

Can you argue the entire sample is too small? Feel free. But let's end the BS that no one under 50 was considered when it makes up almost half the sample.

[cali]

1. as you seem to know something about polling, can you tell me if all phone polling

still uses only land lines?

[SonderWoman]

2. It wasn't landline. It was 60% landline 40% cell phone.

"This sample includes 606 interviews among landline respondents and 400 interviews among cell phone respondents." See page 1.

[cali]

3. thanks

[Travis_0004]

4. Most polls include cellphones

I've been called for polls before on my cellphone (I usually just tell them im not interested)

I would assume the vast majority use cell phones as well as landlines.

The CNN poll used 400 cell phones and 606 landlines.

[nichomachus]

23. And during election season especially

I don't take cell phone calls from anyone I don't know. I send them to voicemail.

If it's important, they'll leave a message.

Also, I was talking to some 30-something guys the other day. They said they rarely answer cell phone calls, even if they know who it is. "If they want to get me, let them text," one of them said to me.

[Cali_Democrat]

5. Most polls now include mobile phones along with land lines

You should know this.

[Godhumor]

6. This one was split 600 land 400 cell approximately

They covered it in the demographics page for the poll.

[PotatoChip]

7. What makes you think that they didn't exclude people under 50?

After all, a previous CNN poll excluded non-whites, and I doubt that there were not significant numbers of non-whites reached.

CNN may have asked the polling firm to specifically poll registered voters aged 50 and over. Polling firms are frequently asked to zero in on various demographics for (whatever) reason.

[Godhumor]

8. Because they provide the numbers

It is not that hard to figure out from the info presented what the approximate sample breakdown happens to be.

[PotatoChip]

9. Either I'm not understanding you, or

you are not understanding me... So please correct me if I'm going down the wrong path...

The polling firm very well may have been asked to politely disengage from an otherwise willing participant -if- he or she did not meet a set criteria. In this case, being 50 or older.

This sort of thing (asking that a certain demographic be polled while excluding another) is not at all uncommon.

[Godhumor]

11. But it didn't happen

Because almost half their sample is under 50 years old. It is a weighted poll, so there may be a disengagement point for certain demographics, but it wasn't zero. It wasn't even close to zero. It was 45% under 50 to 55% over 50.

[PotatoChip]

12. I only noticed the N/A under the under 50 demographic.

Where did you get the info that 45% were under 50?

I'm not at all saying that I don't believe you; I just may have missed that. I'll go back and check page 7, but if that info is elsewhere, could you please let me know where it is?

[Godhumor]

14. I calculated it based off the info given

Backfilling to get what numbers work based off percentage size for over 50 versus final percentage and then calculating results until I reached the minimum numbers needed for the MoE by subsample to work. I am confident I am within 2% of reality based on the assumptions I made in the OP.

I do this for a living.

The simple check is easy. If the poll was only 50 and over then the percentage for each candidate should match the 50 and over results. They don't. That means that the NAs contribute. In Clinton's case, she is 6% lower than her 50+ result.

[PotatoChip]

18. Thanks for taking the time to explain. (nt)

[Godhumor]

22. No worries. Happy to explain. N/t

[PotatoChip]

13. OK, I found this part under methodology....

So I see what you were saying now... My apologies.

Still, my guess is that younger people were less likely to agree to a (possibly) lengthy poll. It does not necessarily mean that they are not registered voters as some in a different thread suggested.

All respondents were asked questions concerning basic demographics, and the entire sample was weighted to reflect national
Census figures for gender, race, age, education, region of country, and telephone usage.
Crosstabs on the following pages only include results for subgroups with enough unweighted cases to produce a sampling error of
+/- 8.5 percentage points or less. Some subgroups represent too small a share of the national population to produce crosstabs with
an acceptable sampling error. Interviews were conducted among these subgroups, but results for groups with a sampling error
larger than +/-8.5 percentage points are not displayed and instead are denoted with "N/A"

.

[restorefreedom]

10. "for whatever reason"

yup. like to reinforce a particular narrative, for example.

[progressoid]

15. I can't put too much support behind a sample size that has a MOE of 8.5% or more.

Regardless of the demographic or pollster involved.

[jeff47]

16. If the sample was too awful to include in crosstabs, why include it in the "headline"?

If the poll more-or-less says "We haven't a clue what under-50 people think" by not including it in the crosstabs, why include those same people in the headline?

(Other than the need to publish any results at all, and a "change" result gets you more eyeballs)

If you don't trust your results in one part of the poll, it doesn't seem like a good idea to trust them in another part of the poll. Yes, you can mathematically make it "good enough" by diluting the accuracy of your "over-50" results.

[dsc]

19. depending on the crosstab you could never have a poll then

LGBT is almost never cross tabbed for this reason. For my money they should have given the percentages, noted the MOE, and moved on.

[jeff47]

20. For a small enough sample, yes that's a problem.

But "Under 50" is a rather enormous group of people. And they couldn't get enough under-50 respondents to make it work.

That doesn't exactly make the poll look like a useful predictor, especially with all the previous polls showing a large difference in support based on age. Even if you can get the MOE down far enough by piling everyone together.

[dsc]

24. they chose not to since it didn't make the MOE they wanted

the sample itself was OK. Piling everyone together is how sampling works.

[Godhumor]

21. Because subsamples can add to a meaningful sample

They just didn't bother to parse out subsamples that individually have too large of an MoE. Part of these issue with this is that the full sample is small, though meaningful, which makes starting conclusions on subsamples extremely hard.

And CNN didn't include it in the headline. There is nothing saying "under 50s preferred x by y amount" because they do not feel they can make conclusions on the under 50 population...even if the subsample is in line with the full population parameters.

[SidDithers]

17. DU rec...

Thanks for adding some reality to the situation.

But that other thread was freakin' hilarious.

Sid

[Godhumor]

25. Going to go ahead and bump as that hilariously wrong other thread is still receiving recs n/t