I want to decipher this graph, but it confuses me: enter image description here


The color indicates the age bracket of the patient, but the age bracket is already in the x axis. For example, what does the gray bar in the bracket 40-49 mean? Should be over 65 according to legend.

1 Answer 1


I agree the presentation is confusing. There are 4 categories, two are the same category except separated by age. The other two categories are not separated by age. There are two gray colors; the darker one is "NHAP patients, not bedridden" (nursing home acquired pneumonia), and is the one you refer to.

You'll note that only 3 categories are present at any age range except 60-69, because that decade includes both above/below 65.

  • @user1721235 It doesn't. It has 3 categories: patients<65 not bedridden, NHAP patients not bedridden, and bedridden. There are 4 possible categories but the >65 one is missing for all the ranges below 60 and the <65 one is missing for all the ranges above 70.
    – Bryan Krause
    Feb 3, 2021 at 21:35
  • Oh I have been confusing the shades of gray! Feb 3, 2021 at 21:36
  • But then why are the NHAP and black bars not equal in the below 65 brackets? Or is the black bar non NHAP? Feb 3, 2021 at 21:37
  • NHAP is only if the pneumonia was specifically acquired in a nursing home facility. I'm on mobile right now and don't have the paper but my assumption is that the other categories are non-NHAP, though if they do overlap then the answer is that the other category contains both NHA and not.
    – Bryan Krause
    Feb 3, 2021 at 21:41
  • 1
    This is what always happens with grayscale charts. The human eye can only distinguish so many shades of grey, and when you add in the variations caused by different display media (paper, phone, PC, etc), grayscale charts always require a lot of effort to interpret unless they're trivially simple. The same thing happens with color charts that use too many colors for lines and bars. Distinguishing a pale blue from a medium-dark blue is almost impossible on many displays.
    – Carey Gregory
    Feb 4, 2021 at 0:28

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