Talk:Corpulence index

Rohrer citation
Rohrer R. Der Index der Körperfulle als Mars des Ernährungszustandes. Münch Med Wochenschr 1921;68:580 — Preceding unsigned comment added by 70.49.163.188 (talk) 15:04, 4 April 2015 (UTC)

No way
Sorry, I just don't believe those formulas. Several of them must be wrong. There's big difference between dividing by a cube and dividing by a cube root. What's going on here? — Preceding unsigned comment added by 70.57.172.70 (talk) 22:55, 15 July 2011 (UTC)

Yes way
Different shapes will certainly yield different volume and mass values as will different body densities. But people are more or less shaped in a similar manner and are more or less similar in density. Moreover, all mass and volume equations for any shape involve either the cubing of a single dimension (e.g., sphere), the product of x y and z dimensions (e.g., box), or some very complex formula for some odd shape.

BMI is a very flawed measurement to begin with as it does not factor for the makeup of a person. A morbidly obese person could have identical BMI values to a lean athlete. The Ponderal index is better because it doesn't discriminate against taller people, but it still ignores the makeup of a person so it is still inaccurate to call it the "leanness of a person". A more accurate leanness index would simply be based on a density value.

If we want a more accurate "skinny index", then we would need to substitute volume for mass in the Ponderal index. That would require a more complex displacement test (e.g., dip the subject in water) or a 3D scan which may be easier today with the existence of cheap digital cameras and free software. — Preceding unsigned comment added by GeorgeOu (talk • contribs) 23:38, 14 April 2012 (UTC)

Normal ranges
In "source 9" it says: The source quoted (Oregon State University) states that typical healthy PI values range between 20 and 25. The source of this is referenced on the same (third) row, although in another cell in the table. I have failed to find a source for what it says in the article (21.75 to 24.0). I thought it might be related to BMI, and I tried taking a person of height 180 cm and finding his weight for a BMI of 25, it's 81 kg. With this height and weight it gives a CI 24.03 (when using the formula in the third row) and would then match one of the numbers, and the CI for 21.75 and a person of 180 cm is 60 kg and using this in BMI it gives 18.52. Checking Wikipedia's page on BMI it clearly states normal weight: 18.5 to 25. Although these numbers match and I know CI is trying to normalize things I'm still not sure they should stay as we would then need a reason to use exactly 180 cm as a reference height. 180 cm isn't the average everywhere and I'm not sure it was wherever BMI was invented. The CI numbers used in this article (21.75 to 24.0) won't match for other heights and BMI of 18.5 to 25. I think it should be changed to reflect what it says on the Oregon State website (20 to 25). Fourth row clearly has the same issue. --NumericalWarfare (talk) 12:08, 23 November 2015 (UTC)

Formulae are inconsistent.
The formulae listed here are confusing. Mass is in the numerator of the first four and the denominator of the fifth formula. Therefore, if mass increases, the CI will increase if using the first four and decrease using the fifth formula. I was momentarily pleased my low Corpulence Index until I applied a few brain cells to the issue. - Bill Whelan2602:306:BDDC:5740:85D1:747C:5876:5546 (talk) 19:48, 17 September 2016 (UTC)

Confused from the start
Apparently, this article does exactly what it says not to do. The title of the article is Corpulence index, yet it begins begins, "The Corpulence measure (not to be confused with corpulence index, which is measured by actual weight/desired weight)..." Later in the article it uses the term, Corpulence index again for mass/height³. — Preceding unsigned comment added by 172.77.226.80 (talk) 20:34, 27 October 2016 (UTC)

Yes, that was an unsourced edit by an anonymous user, I restored the original version. However, someone with more experience in this field than me should see if that confusing edit had some relevance or not. Kenadra (talk) 14:59, 7 March 2017 (UTC)

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Potentially dangerous?
An IP edit has removed the table, calling the figures wrong and potentially dangerous. A few minutes told me that at least half the cites appear legitimate, and the ranges more or less work for several real-world figures. I'm not sure what would be dangerous unless someone misapplies the information. Hence I'll revert the edit. If I've missed the point, please explain here. Thanks. Pastychomper (talk) 09:02, 15 July 2019 (UTC)

I removed it because the figures are wrong. Row 3 gives normal C.I. in the range 20 - 25. I am 187cm tall (6' 2"). According to the table, a normal weight for me (C.I. = 20) would be 52.3kg (115lbs). If common sense doesn't tell you this is wrong, calculate the BMI for this (15) and check here https://en.wikipedia.org/wiki/Body_mass_index#Categories (52.3kg, BMI 15 is 'very severely underweight'). The page at Oregon State is obviously wrong too. It's dangerous for example, because people suffering from anorexia might take this nonsense as justification for their unhealthy weight. I suggest you take a basic stats course or refrain from editing things involving figures. — Preceding unsigned comment added by 95.146.161.216 (talk) 10:43, 19 July 2019 (UTC)
 * Thanks for the explanation, and apologies for not checking as robustly as you appear to have done. I tried several real-world figures rather than calculating the limits, and healthy weights also fit into the range on what was row 3.  I agree that range is too wide, and take your point about anorexics (even though WP isn't supposed to be a source of health advice).
 * I've deleted Row 3 (both its cites pointed to the same source), as far as I can see the remaining 3 rows are accurate and broadly agree with current advice, although the range for babies could do with some more explanation and/or better citation. Pastychomper (talk) 10:02, 23 July 2019 (UTC)
 * Thank you. Sorry for the rude comment at the end, I was angry that you reverted my edit. — Preceding unsigned comment added by 95.146.161.216 (talk) 21:34, 23 July 2019 (UTC)

CI table still incorrect
The units given for the Imperial CI calculation are inconsistent with the formula given.

I believe the fix is to change the units to inches * lb^(-1/3). I assume the units rather than formula has the mistake because the formulas and range are consistent with the referenced web page but the units don't match the formula. Even if these units are given in some reference for this formula it is still an error because the units don't match the formula.

It is confusing that CI should intuitively go up as corpulence increases and does go up for the metric version but goes down for the imperial version. Why should the formulas in metric and imperial units be reciprocals of each other? It looks like someone wanted the number to be near 12 in both versions. I haven't yet read the original reference to dig into this more. 73.11.105.81 (talk) 21:30, 17 October 2022 (UTC)