[HN Gopher] Look at median, and not mean GDP per capita
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Look at median, and not mean GDP per capita
Author : amin
Score : 49 points
Date : 2022-08-07 21:26 UTC (1 hours ago)
(HTM) web link (medianism.org)
(TXT) w3m dump (medianism.org)
| [deleted]
| jstx1 wrote:
| It's hard to take this seriously when the author mixes up the
| basic meaning of GDP.
|
| > For example, when economists think about how "the economy" is
| doing, they have traditionally focused on total income (GDP) or
| per-capita income (mean GDP) as the most important measure.
|
| No, they don't. GDP isn't income at all, they're completely
| different metrics.
|
| And in fact the article never mentions "median GDP" like the
| posted title suggests, it switches to "median income" because
| median GDP isn't even a thing that you can calculate since it's
| not a metric that exists for each individual person (therefore no
| median).
|
| How did this get to the front page?
| maerF0x0 wrote:
| Why 50th percentile? Why not 49th, or 25th?
|
| I've actually had this running theory that all civil servants
| should be paid a fixed percentile of income. This would give them
| all an interest in ensuring that income/GDP goes up and that it
| goes up for those below them. (in percentile)
| [deleted]
| divan wrote:
| There is a great book explaning the philosophy, story and problem
| of using averages in many fields - "The End of Average" by Todd
| Rose. [1]
|
| I originally found it from the fascinating article on how using
| averages in the design of military plane cockpit resulted in many
| pilot deaths. That's the best introduction I've seen about
| uselessness of averages with multiple dimensions (with more than
| 3 dimensions it goes bananas). The article is actually is an
| excerpt from the book, so you can get the sense of the book level
| from it. [2]
|
| [1] http://www.toddrose.com/endofaverage
|
| [2] https://www.thestar.com/news/insight/2016/01/16/when-us-
| air-...
| amelius wrote:
| Don't even look at GDP, look at happiness of people instead.
|
| Fetishizing the GDP will only accelerate the climate problem.
| gruez wrote:
| > Don't even look at GDP, look at happiness of people instead.
|
| Bread and circuses for everyone!
| rightbyte wrote:
| The author is just as wrong as the people he criticizes.
| A much better measure of "the economy" is median income because
| that is a more accurate reflection of the economic well being of
| most people.
|
| This is a problem in many fields including engineering.
|
| A median or average has a measurement error (and just because one
| bar is higher than another it doesn't really mean it is actually
| higher).
|
| The distribution is what is interesting and important.
|
| Which gives, start publishing numbers as (x1,x2,x3,x4,x5) at
| 10,30,50,70,90th percentile or whatever. And give up pretending
| complex system are simple.
| mihaic wrote:
| Fully agree.
|
| Most people use life expectancy at birth to believe that
| everyone died in their 30s in ancient times, even though these
| numbers are skewed because of huge infant mortality.
|
| Introducing something like life-expectancy at birth, 5, 10, 20,
| 40 years would paint a much better picture, but it takes hard
| work and a belief that your audience is not stupid.
| bfung wrote:
| https://medianism.org/medianism/about_the_medianist/
| Who Is This Medianist? Jonathan Andreas is an
| Associate Professor at Bluffton University who received his
| Ph.D. in Economics from the University of Illinois at Chicago.
|
| Ok, cool, not some armchair tech bro that spent 5 minutes
| writing up some blog.
| [deleted]
| dwater wrote:
| This is stats 101. Mean and median are measured of central
| tendency, and the median is generally better for skewed
| distributions. The 5 number summary (or your 5 percentiles)
| gives slightly more information, but ultimately you are
| summarizing a complex distribution with a few simple stats.
| There are upsides (it's fast) and downsides (it's incomplete)
| to doing so. The real problem is how few people understand
| stats 101, which makes them easy to mislead.
| pfisherman wrote:
| I mean if we want to go down that road, then why not just
| publish the first four moments of the distribution?
| superb-owl wrote:
| You're technically correct--the distribution carries a lot more
| information than the average or median alone.
|
| The problem is that many of these decisions are being made
| democratically, or by democratically elected representatives.
| They need to be able to explain the impact of their decisions
| to the average voter.
|
| Having a single number that goes up or down makes communication
| and coordination a lot easier, and I think it's worth
| discussing what the best single number might be.
| coldtea wrote:
| Or those "elected represenatives" could help educate the
| people - to e.g. understand distributions.
|
| But instead they educate them in BS, both in schools, and
| through their government communication. It's more convenient
| to emphasize BS in curriculums than proper life/political
| skills...
| scarmig wrote:
| Choosing a single number necessarily removes information
| about the distribution, though, and which information is
| being discarded is inherently a political decision. The
| Rawlsian veil of ignorance (at least a naive version) would
| have us choose p0 as the meaningful number; a utilitarian
| with certain beliefs about the marginal utility of money
| would prefer the distribution mean. Even the choice to use a
| normalize GDP per capita is taking a strong stance on the
| repugnant conclusion.
| JackFr wrote:
| > They need to be able to explain the impact of their
| decisions to the average voter.
|
| No, not the "average" voter - messaging should be aimed at
| the marginal voter.
| AstralStorm wrote:
| It so happens that the most useful number is usually the
| dominant (also known as mode or most common value), which is
| not visible on the histogram, especially for flat heavy tailed
| distributions such as income these days.
| thaumasiotes wrote:
| > the most useful number is usually the dominant (also known
| as mode or most common value), which is not visible on the
| histogram
|
| Are you kidding? It's the highest point on the histogram; a
| histogram places very heavy visual emphasis on the mode while
| obscuring the mean and median.
| AstralStorm wrote:
| Sometimes true, but it is the only value that can be
| estimated without error in some cases. Neither median nor
| average is useful for a central tendency in a weird
| distribution - and income tends to be one.
|
| Histograms typically bucket data potentially hiding the
| true value of mode or adding error to it. It really should
| be given directly, with a count of occurences.
|
| Mode is not the same as modal class - which is what you
| would get from a histogram.
| pastacacioepepe wrote:
| > Which gives, start publishing numbers as (x1,x2,x3,x4,x5) at
| 10,30,50,70,90th percentile or whatever. And give up pretending
| complex system are simple.
|
| How are then the institutions going to sell us the narrative
| that all is well and growth is always good, once we realize
| poor people stay poor and rich people get richer?
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