This is a discussion of the Quadrat Technique provided by Carol, one of the participants
in the female forum. Standard methods for measuring hair loss are important.
Developing some methods doesn't sound overly difficult, especially if techniques are
borrowed from other fields and tested on the hair and scalp. For example, changes in hair
density over time or differences in hair density on various parts of the head, between
races, individuals, etc. could be measured using a quadrat technique. Basically, small
quadrats, or square sampling frames, would be randomly placed on the scalp and the number
of hairs rooted within each quadrat would be counted. The average number of hairs per unit
area could be calculated from the data along with other statistics such as standard
deviation.
The quadrat does not have to be a physical frame, which would be unwieldy except on very
short hair. It could be a square of standard dimension drawn on the scalp with a pen. In a
longitudinal study (with consent of the subjects, of course), the quadrats could even be
tattooed on the scalp to allow the technician to sample exactly the same locations at each
point in time. Permanent quadrats would strengthen the power of the statistical tests as
well as saving time after the quadrats are initially established.
There are several variations on quadrat sampling and there is quite a literature
on determining minimum sample size and optimum quadrat size needed, statistical analysis
of the data, the effects of using quadrats of other shapes, and other considerations. Most
of this work has been done by botanists interested in quantifying plant densities. I see
no reason why it couldn't be used for hair at an appropriate scale. The fact that so much
has already been done on the sampling and statistical aspects of the technique is a real
boon.
If you are interested in reading up on it, go to the plant ecology literature. Suggested
key words: quadrat sampling (NOT quadrant), plant density, tree density, field techniques.
To go to Measurement Technique's discussion group, please click
MEASURING
HAIR LOSS - discussion group
Other articles on Measuring hair loss:
Measurement Techniques and Hair Loss Classification
Dr. Amorn on Measuring Hair Loss
HairSite Editorial
Questions, please email HairSite@aol.com
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