Coefficient of Variation (CV)

[Nahid Mia]

Dear Expert,
I found different CVs(%) while using

tabstat varname [aw=weight], statistics(n mean cv)

and

svyset psu [pweight=wmweight], strata(stratum)
svy: mean varname
estat cv

Can you please explain the reasons?

In addition, is it possible to calculate estat cv by using codes not this default command.


Advance thanks for you support.

Kind reagrds
Nahid

[Carlo Lazzaro]

Nahid:
1) the second code acknowledges the survey design of your dataset, whereas the first ine does not. No wonder that the two -cv- differ;
2) from the -estat- helpfile -estat cv- works with survey data only. Calculating a -svy:- -cv- by an ad hoc code is probably feasible, but I do not know how to do it.

[Nahid Mia]

Dear Carlo,
Many thanks! I hope someone who has such expertise will come up with such help.

Best regards
Nahid

[Stephen Jenkins]

Nahid Mia Check the Methods and Formulae for each of the two calculations. You may find that one uses a denominator of "N" and the other "N-1". (There are justifiable reasons for this.)