Re: Child Anthropometric data [message #2196] |
Thu, 22 May 2014 05:27 |
anilgvdbm
Messages: 11 Registered: December 2013 Location: India
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Member |
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Dear Sir,
In child recode file these are variables called height/Age percentile, Height/Age standard deviation and Height/Age percent of ref. median so how to classify those values. can we need to divide by 100 or 1000? because i need to classify the nutritional status but values are too high. please can you suggest me As early as possible. Thank you in Advance.
Regards,
Anil
Anil
Scientific officer
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Re: Child Anthropometric data [message #2399 is a reply to message #2196] |
Fri, 13 June 2014 00:18 |
Reduced-For(u)m
Messages: 292 Registered: March 2013
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Senior Member |
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For the standard deviation measures, divide them by 100 to get the proper units. The mean should be somewhere between -1 and -2 for most new-ish DHS rounds. What looks wrong with the other two (what are their means, mins and maxes)?
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Re: Child Anthropometric data [message #2402 is a reply to message #2401] |
Fri, 13 June 2014 01:26 |
Reduced-For(u)m
Messages: 292 Registered: March 2013
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Senior Member |
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The formulae and descriptions can be found here:
http://userforum.dhsprogram.com/index.php?t=rview&goto=2 396#page_top
The "standard deviations (or z-score)" refers to how many standard deviations from the median of the reference group (defined in the link above) the height of the person is, conditional on age and gender. So the median, well nourished 41 month old boy (or 23 month old girl) would have a value of 0, and someone below the median would have a negative score. Most children in developing countries have a value below 0.
The formula is: [(respondent height) -(median height in the reference group) ] / (standard deviation of height in the reference group for that age and gender)
The percentile value is the percentile of the reference group distribution of heights that the person falls into. So a person with a z-score of -2 would be in the 2nd percentile or so, and a z-score of 0 would be in the 50th percentile.
I believe the "percent of ref. median" uses height in cm and the formula would be something like: [ (respondent height) / (median height of the reference group)]. I'm not 100% sure about this one.
The standards I provided in the other post are where you get the medians and standard deviations of the reference group (for each age and gender combination). Before you work with any standardized anthropometric measure, you should be sure you fully understand what the measure is telling you. The links I provided should help with that.
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