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WTF is the point of a graph if you have to read the fine print to avoid misinterpreting it? Why not just use a table? A graph is supposed to convey the relative

by chancho 16y ago

WTF is the point of a graph if you have to read the fine print to avoid misinterpreting it? Why not just use a table? A graph is supposed to convey the relative magnitudes of the data points, not just their ranking. If I just wanted to show who drank more than whom I would just list them in order. Looking at these graphs you'd think that: Almost nobody in the south drinks; The vast majority of blacks do not drink; Catholics are twice as likely to drink as Protestants. And so on, when in fact these are all false conclusions. The real conclusion, which you would easily get from properly scaled graphs, is that the majority of people drink across almost all demographic groups. If you blame me for drawing false conclusions from such graphs I blame the shitty fucking graphs for being misleading. I mean, they don't all even start at 50%. One starts at %40 and one at %0. Seriously, these graphs are garbage.

jey 16y ago
Er, so all graphs of temperature should start at absolute zero? It's absurd to expect all graphs to start at zero -- the point of a bar graph is to show relative comparisons, and the whole point of the labels on the axes is to relate the graph to an absolute scale. You even admit this, "[a] graph is supposed to convey the relative magnitudes of the data points" -- Exactly, and so the graph should be scaled in a way that efficiently conveys the relative information. I apologize for the ad hominem, but this is just serious PEBKAC: you need to learn to read graphs. The mistaken conclusions you arrived at could have been avoided if you paid attention to the labels. Yes, a poorly made graph can make a tiny effect look huge, e.g. if it was the case that 99% of people drank, and the graph was just plotting variation within the remaining 1%, that could be pretty misleading. This is yet another reason that the consumers of information should pay attention to the labels and understand what the real message is from the data. Don't expect the creators of the graph to present the data in the "fairest" way (whatever that is); instead it's our responsibility to think critically and make sure we understand what's really going on. The creator of the graph will naturally act to advance his own interests. tl;dr: It's a mistake to consider the labels to be "fine print".
- chancho 16y ago
  You make a good point about temperature, but I stand by my critique because temperature is a quantity and these graphs are all plotting percentages, which should always been graphed from 0% to 100%. If your percentages are all within the range of 99% to 100% then you shouldn't be plotting them as percentages, and if you did then your graph would effectively convey the point that there really isn't a lot of variation among the data. I'll reiterate my opinion that the purpose of a bar chart is not to give relative orderings (if you want that just list them in order) but to illustrate the magnitude of the differences between data points with respect to the natural range of the data. Percentages have a natural range of values: 0-100. Temperature does not have a natural fixed range, unless we're talking about the weather which is incidentally why I like Fahrenheit.
  - jey 16y ago
    > with respect to the natural range of the data. There's hardly ever such a thing as a "natural" range. Even if there is, as in the case of percentages, what's the point on wasting half of the graph on variation that has a mundane explanation? Like if you're plotting popularity of religions in the USA, do you really want to spend about 90% of the vertical space of your graph on Christianity? The point a graph is to shed light on the part of the variation that doesn't have a mundane explanation -- i.e., the interesting part. What you should be complaining about are graphs that don't have labels, as used by some drug companies in advertisements[1]. Maybe that "graphs without labels are bad" meme has maybe been misinterpreted here. 1. In the USA drug companies are permitted to advertise prescription medications.
    - chancho 16y ago
      > There's hardly ever such a thing as a "natural" range. Another good point, but if bar A is twice as tall as bar B then variable A's value had better be twice that of B's. Anything else is precisely the kind of shady drug-company data manipulation that you're so concerned about. If vertical space is at an absolute premium (not the case here IMO) and you have to cut the bars then draw little cut marks on them to let the reader know that the bottoms aren't at zero. (Of course I'm talking about cases when there is a familar concept of zero, like percentages or money or population, not temperature. And if the value goes negative then the bar grows down, cf. any recent chart of US economic indicators.) If you don't base your bars at zero then your bar chart exaggerates differences between data because the reader looks at two bars and compares their relative sizes the same way he looks at the levels in two glasses of beer to compare their volumes.
deleted 16y ago
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by chancho 16y ago

jey 16y ago

Er, so all graphs of temperature should start at absolute zero? It's absurd to expect all graphs to start at zero -- the point of a bar graph is to show relative comparisons, and the whole point of the labels on the axes is to relate the graph to an absolute scale. You even admit this, "[a] graph is supposed to convey the relative magnitudes of the data points" -- Exactly, and so the graph should be scaled in a way that efficiently conveys the relative information. I apologize for the ad hominem, but this is just serious PEBKAC: you need to learn to read graphs. The mistaken conclusions you arrived at could have been avoided if you paid attention to the labels. Yes, a poorly made graph can make a tiny effect look huge, e.g. if it was the case that 99% of people drank, and the graph was just plotting variation within the remaining 1%, that could be pretty misleading. This is yet another reason that the consumers of information should pay attention to the labels and understand what the real message is from the data. Don't expect the creators of the graph to present the data in the "fairest" way (whatever that is); instead it's our responsibility to think critically and make sure we understand what's really going on. The creator of the graph will naturally act to advance his own interests. tl;dr: It's a mistake to consider the labels to be "fine print".

chancho 16y ago
You make a good point about temperature, but I stand by my critique because temperature is a quantity and these graphs are all plotting percentages, which should always been graphed from 0% to 100%. If your percentages are all within the range of 99% to 100% then you shouldn't be plotting them as percentages, and if you did then your graph would effectively convey the point that there really isn't a lot of variation among the data. I'll reiterate my opinion that the purpose of a bar chart is not to give relative orderings (if you want that just list them in order) but to illustrate the magnitude of the differences between data points with respect to the natural range of the data. Percentages have a natural range of values: 0-100. Temperature does not have a natural fixed range, unless we're talking about the weather which is incidentally why I like Fahrenheit.
- jey 16y ago
  > with respect to the natural range of the data. There's hardly ever such a thing as a "natural" range. Even if there is, as in the case of percentages, what's the point on wasting half of the graph on variation that has a mundane explanation? Like if you're plotting popularity of religions in the USA, do you really want to spend about 90% of the vertical space of your graph on Christianity? The point a graph is to shed light on the part of the variation that doesn't have a mundane explanation -- i.e., the interesting part. What you should be complaining about are graphs that don't have labels, as used by some drug companies in advertisements[1]. Maybe that "graphs without labels are bad" meme has maybe been misinterpreted here. 1. In the USA drug companies are permitted to advertise prescription medications.
  - chancho 16y ago
    > There's hardly ever such a thing as a "natural" range. Another good point, but if bar A is twice as tall as bar B then variable A's value had better be twice that of B's. Anything else is precisely the kind of shady drug-company data manipulation that you're so concerned about. If vertical space is at an absolute premium (not the case here IMO) and you have to cut the bars then draw little cut marks on them to let the reader know that the bottoms aren't at zero. (Of course I'm talking about cases when there is a familar concept of zero, like percentages or money or population, not temperature. And if the value goes negative then the bar grows down, cf. any recent chart of US economic indicators.) If you don't base your bars at zero then your bar chart exaggerates differences between data because the reader looks at two bars and compares their relative sizes the same way he looks at the levels in two glasses of beer to compare their volumes.

deleted 16y ago

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