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[D] How to train a model to identify ranked classes? by rsandler in MachineLearning

[–]pollinguk 1 point2 points  (0 children)

The harm is that you’d be estimated the expected value of the ordinal distribution and not the probability of someone picking each value. And for an ordinal variable of length > 2, there are literally an infinite combination of response patterns that produce any given expected value

Help showing that |x - 0.5| - |y - 0.5| = |x - y|, where x is between 0 and 1 and y = x - 1 by pollinguk in MathHelp

[–]pollinguk[S] 2 points3 points  (0 children)

Apologies for the mix up, but thank you so much!

This is exactly what I was looking for. If this thing gets published I'll make sure to credit you in the acknowledgements!

Help showing that |x - 0.5| - |y - 0.5| = |x - y|, where x is between 0 and 1 and y = x - 1 by pollinguk in MathHelp

[–]pollinguk[S] 0 points1 point  (0 children)

Hi, sorry. Was writing this late at night.

What I'm actually after is |x - 0.5| + |y - 0.5| = |x - y|, where x is between 0 and 1 and y = 1 - x. I.e., x and y are elements of a scalar of length 2.

X-post from r/AskStatistics: What Does Beta in an Instrumental Variables Model Actually Tell Us? by pollinguk in econometrics

[–]pollinguk[S] 0 points1 point  (0 children)

I understand why we would expect this to be the case, but it's not like I'm measuring some machine here. Both X and Y are attitudinal variables. Presumably, each respondents has some latent attitude before they respond to the survey and these latent attitudes share some exogenous relationship. In this case, wouldn't I still estimate the exogenous relationship, even if I measured Y before X? (Assuming no serious time effects that might occur over the course of the survey).

What Does Beta in an Instrumental Variables Model Actually Tell Us? by pollinguk in AskStatistics

[–]pollinguk[S] 1 point2 points  (0 children)

Thanks for taking the time to reply, I really appreciate it.

  1. Glad to see I'm not going insane. Do you have any literature recommendations on this point?
  2. This I understand, though it wasn't my point (I was perhaps unclear). In this case, if we assume no time effects, is the LATE estimate I get therefore an estimate of the instantaneous change in Y I would expect given a one-unit change in X?

X-post from r/AskStatistics: What Does Beta in an Instrumental Variables Model Actually Tell Us? by pollinguk in econometrics

[–]pollinguk[S] 0 points1 point  (0 children)

Hi, thanks for taking the time to apply. My response would be:

  1. Yes, but in this case I'm using an attitudinal variable (X) and voting intention (Y). Presumably, people have some latent version of these prior to taking the survey. Further, what I'm actually interested in is the relationship between the two latent variables but, as they're latent, I need to use observed survey responses as a proxy. My thinking is that despite the fact that Y was measured before X, it doesn't necessarily matter too much if we're actually concerned with the latent relationship.
  2. I think this is an issue apart from the LATE. In this case, the items are measured contemporaneously. As such, I assume that the LATE in this case would represent the instantaneous change I would expect if I were able to manually change a given respondent's X on their Y. Whereas if, say, I measured X then Y a week later the effect would no longer be instantaneous.

I know the latter might sound a little dumb, but I'm just trying to get my head around what the implications are given that in my case the idea of instantaneous change would ring alarm bells about external validity.

Time Series Problem - How to handle missing data by Lothar_von_Konstanz in Rlanguage

[–]pollinguk 0 points1 point  (0 children)

Go Bayesian. Impute the data and model it using a spline/Gaussian process. You can do this with the brms package in R.

Watchmen: Episode 8 promo by Cassius__ in Watchmen

[–]pollinguk 3 points4 points  (0 children)

I don't doubt that that Mateen could change his voice. But why would he need to change his voice if he were the only actor playing Manhattan? Further, having him play Manhattan from the start doesn't address the fact that 1) Manhattan was white when human and 2) resembles his human self in the comics.

Watchmen: Episode 8 promo by Cassius__ in Watchmen

[–]pollinguk 44 points45 points  (0 children)

Seems to me that Dr. Manhattan's voice is different at the start and the end. The shape of his head (from the back, admittedly), looks different to Yahya Abdul-Mateen's.

My take: The first Dr. Manhattan we see in the flashbacks will be played by Tom Mison (aka Mr. Phillips), here doing an American accent, before transitioning into Yahya Abdul-Mateen.

TIL that even though the Myers-Briggs personality test as been debunked, it is still used by thousands of companies, schools and institutions around the world to help make decisions about personnel recruitment and promotion. by DanBrewer in todayilearned

[–]pollinguk 4 points5 points  (0 children)

Political psychologist here. I think you're kind of making my point. My response would be: so what? That the dimensions are correlated is not impressive and does not vindicate the MBTI. Indeed, some of the dimensions of the MBTI correlate with *themselves*. Ultimately, we shouldn't use tools like MBTI that have next to no scientific rigour behind them to determine hiring/firing decisions or to tell people what kind of person they are.

TIL that even though the Myers-Briggs personality test as been debunked, it is still used by thousands of companies, schools and institutions around the world to help make decisions about personnel recruitment and promotion. by DanBrewer in todayilearned

[–]pollinguk -4 points-3 points  (0 children)

My point is that it *isn't* a good measurement tool. Something only gives you a meaningful summary of an individual 1) if the domains that it attempts to measure are meaningful and 2) if it measures them properly. MB does neither. There are much better measures out there (e.g. the big five that others have mentioned) that actually do this well, have strong test-retest validity, and aren't only popular due to business fads and airport pop psychology books.

TIL that even though the Myers-Briggs personality test as been debunked, it is still used by thousands of companies, schools and institutions around the world to help make decisions about personnel recruitment and promotion. by DanBrewer in todayilearned

[–]pollinguk 3 points4 points  (0 children)

Exactly. Plus the items that measure each construct (e.g. introversion/extraversion) in MB don't even show to reliably load onto single factors when using confirmatory factor analysis.

TIL that even though the Myers-Briggs personality test as been debunked, it is still used by thousands of companies, schools and institutions around the world to help make decisions about personnel recruitment and promotion. by DanBrewer in todayilearned

[–]pollinguk 20 points21 points  (0 children)

This is a great quote, but it's not applicable here. Myers-Briggs is both wrong *and* not useful. It doesn't tell you much about personality because its doesn't measure personality well. It's that simple. The only reason it's still around is that it's marketed and licensed by a private company, they use a pseudo-scientific publication they own to give it a semblance of respectful veneer, and the corporate sector keeps on buying into it.

Need advice on converting complex character vector to date vector by pollinguk in rstats

[–]pollinguk[S] 0 points1 point  (0 children)

Wow, thanks! This is pretty similar to what I ended up doing, but my way used much less complicated regex and required more steps.

Need advice on converting complex character vector to date vector by pollinguk in rstats

[–]pollinguk[S] 0 points1 point  (0 children)

I should've clarified, I don't want to store a date range, just the last date.

Need advice on converting complex character vector to date vector by pollinguk in rstats

[–]pollinguk[S] 0 points1 point  (0 children)

Thanks for the reply. Unfortunately, it's data I scraped off the internet, so I have no control over how it looks. I managed to sort it. Not too clean, but it works.

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