3 ms·

Not zeroing a graph is usually a sign of trying to send a message or manipulate the reader. In that graph, basing the Y on 50T shows a worrying drop, that is no

Not zeroing a graph is usually a sign of trying to send a message or manipulate the reader. In that graph, basing the Y on 50T shows a worrying drop, that is not true as you can see if you base on 0T. You can base in 25T and it will show a moderate fall. Or you can base on 50T and making the graph taller to show a catastrofic fall. If you need a graph focusing on a narrow range, make a new category, like "loss in %" and you will move in the 0-6 range instead of 50-53.

ajuc 3y ago
Here's your temperature graph. | |--------------- (something near room temperature) | | | | +--------------- (absolute 0) 0 isn't magic, there's different starting points depending on the data, it's not a manipulation as long as you clearly mark that the truncation happened. I like the idea of not including the axis line, I'm fine with the graph break on the axis as well. Anything as long as it's obvious.
- otherme123 3y ago
  You can zero at an arbitrary point, but the point is that it forces you to explain your zero. For example, for "room temperature" you might zero at 0ºC, a value that can be easily reached in winter. For "body temperature" you can zero at 37ºC and stretch the scale +-5ºC (aprox. the survivable range), and the graph would show fever vs non-fever. You clearly are not after some deception. For a graph of earnings or net income, you should zero at either 0T (you can have zero earnings or even negative earnings, or you can have zero income), or zero at some point that you must explain and makes sense (e.g. zeroing Boeing earnings at Boeing + MD merger). But in my experience, when someone zeros the scale at an arbitrary point, he's after a deception. I've seen graphs zeroed randomly and without explanation at 5000, and the scale going from 5000 to 5004, with the points going wildly from the top to the bottom and back again. "Wow, what a wild ride!", but in reality it was as stable as it could be. There are a lot of examples of this in business anual/quarter reports.
- IshKebab 3y ago
  > there's different starting points depending on the data I dunno, your temperature example is a perfect counter-example to this. What absolute starting point would you use for temperature?
  - ajuc 3y ago
    If it's human temperature I would use something near 36.6 C, obviously? Probably 35 C. If it's air temperature outside I would use 0 C. If it's cooking temperature I would still use 0 C, not absolute zero. Actually the only case in which absolute zero seems like the sensible answer I can think of is superconductors' critical temperatures and other physical stuff.
    - IshKebab 3y ago
      None of that makes any sense. There's nothing special about 35C or 0C. The whole point of the article is that it's visually misleading to have lines at arbitrary points. For your first example a line at average body temperature would make sense though.
      - bigfudge 3y ago
        But there is something special about both of those temperatures because they matter greatly to humans. This graphs should be designed to make referencing agains those values easy, where that is going to be useful.
      - ajuc 3y ago
        Hypothermia starts under 35 C Around 0 C it starts snowing instead of raining, and standing bodies of water freeze. If you have plants outside and it's not winter - they will die if it gets under 0 C. If you're driving - the road will freeze under 0 C and it's pretty dangerous to drive fast in such conditions. I'd argue there's no more important air temperature than 0 C on Earth-style planets. For cooking 100 C is a reference (water boils), but it's a bad starting temperature because you start lower than that. It's important to show room temperature (around 20 C), boiling temperature (around 100 C) and the maximum useful temperature (around 250 C). So starting at 0 C makes sense.

ajuc 3y ago

Here's your temperature graph. | |--------------- (something near room temperature) | | | | +--------------- (absolute 0) 0 isn't magic, there's different starting points depending on the data, it's not a manipulation as long as you clearly mark that the truncation happened. I like the idea of not including the axis line, I'm fine with the graph break on the axis as well. Anything as long as it's obvious.

otherme123 3y ago
You can zero at an arbitrary point, but the point is that it forces you to explain your zero. For example, for "room temperature" you might zero at 0ºC, a value that can be easily reached in winter. For "body temperature" you can zero at 37ºC and stretch the scale +-5ºC (aprox. the survivable range), and the graph would show fever vs non-fever. You clearly are not after some deception. For a graph of earnings or net income, you should zero at either 0T (you can have zero earnings or even negative earnings, or you can have zero income), or zero at some point that you must explain and makes sense (e.g. zeroing Boeing earnings at Boeing + MD merger). But in my experience, when someone zeros the scale at an arbitrary point, he's after a deception. I've seen graphs zeroed randomly and without explanation at 5000, and the scale going from 5000 to 5004, with the points going wildly from the top to the bottom and back again. "Wow, what a wild ride!", but in reality it was as stable as it could be. There are a lot of examples of this in business anual/quarter reports.
IshKebab 3y ago
> there's different starting points depending on the data I dunno, your temperature example is a perfect counter-example to this. What absolute starting point would you use for temperature?
- ajuc 3y ago
  If it's human temperature I would use something near 36.6 C, obviously? Probably 35 C. If it's air temperature outside I would use 0 C. If it's cooking temperature I would still use 0 C, not absolute zero. Actually the only case in which absolute zero seems like the sensible answer I can think of is superconductors' critical temperatures and other physical stuff.
  - IshKebab 3y ago
    None of that makes any sense. There's nothing special about 35C or 0C. The whole point of the article is that it's visually misleading to have lines at arbitrary points. For your first example a line at average body temperature would make sense though.
    - bigfudge 3y ago
      But there is something special about both of those temperatures because they matter greatly to humans. This graphs should be designed to make referencing agains those values easy, where that is going to be useful.
    - ajuc 3y ago
      Hypothermia starts under 35 C Around 0 C it starts snowing instead of raining, and standing bodies of water freeze. If you have plants outside and it's not winter - they will die if it gets under 0 C. If you're driving - the road will freeze under 0 C and it's pretty dangerous to drive fast in such conditions. I'd argue there's no more important air temperature than 0 C on Earth-style planets. For cooking 100 C is a reference (water boils), but it's a bad starting temperature because you start lower than that. It's important to show room temperature (around 20 C), boiling temperature (around 100 C) and the maximum useful temperature (around 250 C). So starting at 0 C makes sense.