Home » Countries » Ethiopia » Height and Weight Scores (WHO Child Growth Standards) data (DHS 2005 Problem in merging Height and Weight Scores (WHO Child Growth Standards) with Births Recode)
| Height and Weight Scores (WHO Child Growth Standards) data [message #19150] |
Tue, 28 April 2020 10:02  |
efourni2
Messages: 1
Registered: April 2020
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Member |
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Dear DHS Forum,
I'm interested in different variables related to children in the Births Recode of DHS. For example: b6 (age at death), hw57 (anaemia level), hw70 (Height/age standard deviations according to WHO), hw71, hw72, hw73.
In DHS 2005, variables hw70 to hw73 are in a separate file: ETHW51DT.ZIP accompanied by a MERGE.doc giving the following instructions:
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HEIGHT AND WEIGHT WHO CHILD GROWTH STANDARD FILES
The Height and Weight WHO Child Growth Standard files contain the standard deviations for the height for age, weight for age, weight for height, and BMI according to the new WHO definition. These data are available in the standard distributed DHS-V data files but not for previous recode definitions. The new WHO scores for recode definitions 4 and below need to be merged with the corresponding standard recode files for analysis purposes.
In the early phases of DHS, the Height and Weight data was collected for children of interviewed women; but in the last two rounds the data were collected for all children in the households. Variable HWLEVEL in this file indicates whether the anthropometry data was collected at the household or the woman's level. Code 1 in that variable indicates that height and weight was collected at the household level and code 2 indicates that it was collected at the woman's level.
The Height and Weight data collected for children of interviewed women can be merged with either their mothers or the children themselves as follows:
•Use HWCASEID from the Height and Weight file with CASEID from the Individual Recode to merge it with the mother's data.
•Use HWCASEID and HWLINE, from the Height and Weight file, with CASEID and MIDX, from the Children's recode file to merge it with the Children's data.
•Use HWCASEID and HWLINE, from the Height and Weight file, with CASEID and BIDX, from the Births Recode file to merge it with the Births' data.
The Height and Weight data collected for children at the household level can be matched to the households, to the members, to the mothers, or to the children.
•Use HWHHID from the Height and Weight data file with HHID from the Household Recode file to merge it with the household data where the child was measured.
•Use HWHHID and HWLINE from the Height and Weight file with HHID and HVIDX from the Members Recode file to merge it with the household member data.
Once the Height and weight data are merged to the household members' file, the resulting file could then be merged with the mother's and children's file, as follows:
•Use HV001 (cluster number) plus HV002 (household number) and HC60 (mother's line number) from the constructed file and merge it with the corresponding V001, V002 and V003 from the Individual Recode file.
•Use HV001 (cluster number) plus HV002 (household number) and HWLINE from the member's constructed file (or the one resulting from the previous merge), and merge it with the corresponding V001, V002, B16 (child's line number in the household) in the Children Recode file or in the Births Recode file.
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I have tried to follow these steps in Stata in order to merge the Height and Weight Scores file to the Birth Recode. I have successfully merged Height and Weight score data to the Household member Recode.
However, when I want to merge (1 to 1) the previous merged file to the Birth Recode file, I encounter the following problem: "variables v001 v002 b16 do not uniquely identify observations in the master data".
By looking at the data, it seems that many children have missing value for the variable b16 even if they do have entries for variable b6 (age at death) and hw57 (anaemia).
Therefore, does somebody know how I could merge accurately the Births Recode data with the Height and Weight Scores data?
Here is my Stata code:
*rename variables and sort data for merging
use "ETHW51FL.DTA", clear
ren hwhhid hhid
ren hwline hvidx
sort hhid hvidx
save "HW_clean.dta", replace
*merge to HH data
use "ETPR51FL.DTA", clear
sort hhid hvidx
merge 1:1 hhid hvidx using "HW_clean.dta"
save "HW_Member.dta", replace
use "HW_Member.dta", clear
rename hv001 v001
rename hv002 v002
rename hvidx b16
rename hc70 hw70
rename hc71 hw71
rename hc72 hw72
rename hc73 hw73
keep v001 v002 b16 hw70 hw71 hw72 hw73
sort v001 v002 b16
save "HW_to_merge.dta", replace
*merge to birth data
use "ETBR51FL.DTA", clear
sort v001 v002 b16
merge 1:1 v001 v002 b16 using "HW_to_merge.dta"
Thank you for your help.
Emilie
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| Re: Height and Weight Scores (WHO Child Growth Standards) data [message #19200 is a reply to message #19150] |
Fri, 08 May 2020 14:53  |
Bridgette-DHS
Messages: 3215
Registered: February 2013
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Senior Member |
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Following is a response from DHS Research & Data Analysis Director, Tom Pullum:
I always use the old version of merge, without "1:1", etc, because it tends to give me problems. After your first merge, do you have a new variable called "_merge"? If so, you need to drop it.
The main problem is that the hc7x variables are only applicable to children under 5 who are in the household survey. You should use the KR file rather than the BR file, because the BR file includes ALL births in the birth histories, not just those in the past five years. Next, both the BR and KR files include children who have died or are not in the same household as the mother. You need to eliminate those cases. You can have multiple children with the same mother who have died or are living elsewhere and that's why you get the "not unique observations" message. Let us know if the following does not work.
I suggest that you revise this
*merge to birth data
use "ETBR51FL.DTA", clear
sort v001 v002 b16
merge 1:1 v001 v002 b16 using "HW_to_merge.dta"
to become this:
*merge to birth data
use "ETKR51FL.DTA", clear
drop if b16==0 | b16==,
sort v001 v002 b16
merge 1:1 v001 v002 b16 using "HW_to_merge.dta"
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