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[OQSPS] Cognitive ability and political preferences in Denmark

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Bob,

Thanks for looking over the study.

Quote:In the abstract there is a general description of what was done, but no clear statement of objective. I think most readers would want to see something that clearly states something about the purpose of the study.

I have rewritten the abstract to briefly note why we carried out the study. I added: Multiple studies have reported positive relationships between cognitive ability and preferences for freedom, both at the personal level (e.g. drug use) and the economic (e.g. smaller government). To add to this, we investigated the ...


Quote:I am confused by this:
By going through a pollster, we administered 24 additional items to the sample:
After reading again, I assume that this simply means that when you used the pollster, you added the additional items. If so, the confusion I experienced was related to the word "by." It could be written to say "When the polling was repeated with a pollster, we added 24 additional items." ... Or something to that effect.


The final sample size was n = 327 (65% of the original n).
On first reading, it was unclear as to why the final sample size was smaller. I now assume that 327 was the number of people who responded to the pollsters, although it was not obvious to me that they contacted all of the first group or only part. Can this be worded differently?
Later (section 2.3) there is a comment about removing responses where random answering was indicated, but that resulted in a 20% reduction. Was the 20% reduction before or after the initial reduction? I assume that is what happened.

I have rewritten the text in multiple places to be more clear.

What was done was that:

An earlier study surveyed some n=552 Danes on various variables for the stereotype study (). We arranged with the pollster to send out invitations to take part in a second survey to the same 550 persons. Some of them had either quit taking part in surveys all together or simply did not want or have time to take part in our second survey. For this reason, the sample size is smaller than the one before at n=333. Some people failed one or (usually) more of the control questions and due to an error at the pollster, some could not be linked up between the two surveys. This left us with n=259 persons with complete data for the analyses.



Quote:As Table indicates, responders were slightly younger, had slightly lower cognitive ability and were slightly less educated than non-responders. There was, therefore, some selection bias in responding to our survey.

Some readers will recall that the usual pattern of participation is skewed towards brighter people, due to their greater willingness to participate. This case went the other way. I assume this is random, but it might be worth a sentence or two to explain the likely cause of this somewhat unexpected response makeup.

I considered it, but since the difference is small (d=23), the reversed finding probably reflects a chance happening and is not worth commenting on.


Quote:Just a comment on the Likert scales: It seems to me that by dividing the scales into two ranges, an unnecessary distraction resulted. This meant lots of discussion about combining the results when there was nothing gained with respect to the paper. Using either one would have, in my opinion, been better and would not have resulted in any loss of value. Given that this was already done, there is no way to change it now.

I agree, but we didn't know that before carrying out the study! :) Now we know that it doesn't matter whether one uses 7-point or 101-point scales.


Quote:Figures 3 and 4
Some of the item characteristic curves seem to have low slopes, making the inflection point indistinct. I understand that you can define the latent trait despite this, but it appears to me that those curves are not what you would want. The factor analysis shows 4 distributions that show reasonable looking shapes, but the others seem to be uninformative. There was little discussion of this, but there was a mention of too few easy items. Can more be said about the impact of this skew on the outcome? It leaves me wondering how one can justify using uneven item difficulty to indicate the relations that are discusses with respect to population preferences versus intelligence.


The figures (one was missing and has been added) are primarily for the readers more expert in IRT. However, I have rewritten some of the text to be more informative. The missing figure was the one showing the sum of the information from the items, which makes it clear that there was a lack of discriminative ability on the left tail. But in general, it was not that large a problem: mean pass rate was 37% with the very difficult item and 41% without which is pretty close to the optimal value of 50%.

I realize that the IRT figures are ugly. However, it is not easy to produce better ones because the figures are generated by the package that calculates the IRT results (psych) and they are based on the archaic base plotting system, not the modern ggplot2 system.


Quote:The above may be related to my comments concerning figures 3 and 4. The papers I have read on the subject of political orientation on left-right scale or liberal-conservative scales have shown that there is a correlation with intelligence (as you acknowledge near the end of the paper), although the results have been somewhat mixed. So, I too am surprised by this result and ask if it can be traced to the failure to use a population representative measurement of intelligence. I am a bit more confused in that the ICAR5 should have given an adequate measurement. I admit to confusion, which may be entirely mine and not a problem with the methodology.


The somewhat mixed results comes from some researchers trying to model political preferences with only 1 dimension (liberal-conservative). The mixed results to some degree reflect the different ways different researchers have operationalized this supposed 1-dimensional trait. If they used many items related to 'social conservatism' (e.g. opposition to legalized abortion) they obtain negative correlations, but if they use fiscal/economic measures, the relationships turn positive. If they used some kind of mix, the results will be unclear.

--

As it happens, there had been a bug in the IRT software (scoreIrt(), https://cran.r-project.org/web/packages/psych/news.html). The bug meant that the scores from IRT were incorrect and was especially problematic for short scales (such as ours), which affected the cognitive ability estimates from this study. The bug has now been corrected and this increased the correlations to the point that they are more in line with the theoretical expectations, especially after correction for measurement error. In fact, most of the tables and figures had to be replaced because of this error.

This also meant that much of the discussion had to be rewritten which I have done. I have also inserted proper tables in the paper as well and prettier and better labelled figures.

I have updated the files.

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Messages In This Thread
[OQSPS] Cognitive ability and political preferences in Denmark - by Emil - 2016-Sep-17, 17:10:12
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by ljzigerell - 2016-Sep-25, 22:43:52
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by NoahCarl - 2016-Sep-29, 16:37:19
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Peter Frost - 2016-Sep-29, 20:57:30
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Emil - 2016-Sep-28, 13:40:24
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Emil - 2016-Sep-30, 03:10:05
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Emil - 2016-Oct-04, 13:37:39
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by ljzigerell - 2016-Dec-06, 06:14:48
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Emil - 2016-Dec-06, 18:46:06
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by BobWilliams - 2017-Jan-11, 00:23:07
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Emil - 2017-Jan-13, 07:59:24
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by BobWilliams - 2017-Jan-13, 15:40:46
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by BobWilliams - 2017-Jan-14, 16:30:49
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Emil - 2017-Jan-14, 22:23:52
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by BobWilliams - 2017-Jan-21, 21:01:22
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Peter Frost - 2017-Jan-29, 16:37:35
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Emil - 2017-Jan-29, 20:05:13
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Emil - 2017-Feb-11, 14:29:03
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Peter Frost - 2017-Feb-11, 20:21:25
RE: [OQSPS] Cognitive ability and political preferences in Denmark - by Emil - 2017-Feb-12, 19:52:05
 
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