Measuring and Plotting
Plotting using the new UKWHO Growth Charts
Presentation D
Adapted from training materials of the Royal College of Paediatrics and Child Health [RCPCH]
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Measuring and Plotting
Plotting the Chart
• Record measurement and date in ink, plot in pencil
• Use a dot; do not join up
• Age errors are commonest source of plotting
mistakes
use a calendar or date wheel to calculate age
– Age in weeks for first 6-12 months
– Calendar months thereafter
• Count forward from the date of birth to current month using
day birth e.g. if date of birth is 26/6/09, then age 13 months is
on 23/7/10
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Measuring and Plotting
What do the Centiles Show?
• Optimum range of weight and heights
• Describes the percentage expected to be below that line
– 50% below 50th
– 91% below 91st
– 1 in 250 below 0.4th
• Half of all children should be between 25-75th centile
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Measuring and Plotting
Centile Terminology
If the point is exactly on the
centile line, or within ¼ of a
space of the centile line,
the child is described as
being ‘on the X centile’ (see
A) e.g. on the 91st centile.
If not they should be
described as being
‘between centile X and Y’
(see B) e.g. between the
75th -91st centile.
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Measuring and Plotting
Centile Spaces
A ‘centile space’ is the
distance between two centile
lines (e.g. C).
Two measurements can be
described as a centile space
apart if they are both midway
between centiles (e.g. D).
Falls or rises should be
expressed as multiples of
centile spaces (e.g. a fall
through 2 ½ centile spaces).
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Measuring and Plotting
Summary: Plotting and Centiles
• Record measurement and date in ink
• Plot one single dot in pencil-[no ‘fried eggs’, or joining up]
• Age errors are commonest source of plotting mistakes
• Centiles describes the percentage expected to be below
that line
• A child is
– on a centile if within ¼ space of line
– between the two centiles if not on (or within ¼ space of) a centile
• A centile space is the distance between two centile lines
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Measuring and Plotting
Measuring and plotting: Activity 2 Answers
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Measuring and Plotting
Measuring and plotting: Activity 2 Answers
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Measuring and Plotting
Measuring and plotting: Activity 2 Answers
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