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help for ^svylc^
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Estimates for linear combinations after ^svy^ estimation commands
---------------------------------------------------------------

	^svylc^ [exp] [^,^ ^show^ ^or^ ^l^evel^(^#^)^ ^deff^ ^deft^ ^meff^ ^meft^ ]


exp is an expression that is valid for the ^test^ command.  See help @test@
and [5s] test.


Description
-----------

^svylc^ produces estimates for linear combinations after a ^svy^ estimation
command; namely, ^svymean^, ^svytotal^, ^svyratio^, ^svyreg^, ^svylogit^, or ^svyprobt^.

By default, ^svylc^ computes the point estimate, standard error, t statistic,
p-value, and confidence interval.  Design effects (^deff^ and ^deft^) and
misspecification effects (^meff^ and ^meft^) can optionally be displayed.

^exp^ is any expression having valid syntax for the test command; see help @test@.
Note, however, that the expression must NOT contain (1) an equal sign, or
(2) any constants.

The ^svytest^ command can be used to test multidimensional hypotheses, see
help @svytest@.


Options
-------

^show^ requests that the labeling syntax for the previous ^svy^ estimates be
    displayed.  This is useful when the ^svy^ estimation command produced
    estimates for subpopulations using the ^by()^ option.  When ^show^ is
    specified, no expression is given.

^or^ (after ^svylogit^ only) reports the estimated coefficients transformed to
    odds ratios, i.e., exp(b) rather than b.  Standard errors and confidence
    intervals are similarly transformed.

^level(^#^)^ specifies the confidence level (i.e., nominal coverage rate),
    in percent, for confidence intervals; see help @level@.

^deff^ requests that the design-effect measure deff be displayed.

^deft^ requests that the design-effect measure deft be displayed.  deft is the
    square root of deff when there is no finite population correction (FPC).
    When the ^fpc()^ option has been specified, deft differs slightly from the
    square root of deff (since Kish's formula for deft always uses a
    simple-random-sampling variance estimate without an FPC regardless of
    whether an FPC was used for the survey design-based variance estimate).

^meff^ requests that the meff measure of misspecification effects be displayed.

^meft^ requests that the meft measure of misspecification effects be displayed. 
    In all cases, meft is the square root of meff.


Examples
--------

 . ^svymean bp1 bp2^
 . ^svylc bp1 - bp2^

 . ^svyreg y x1 x2 x3 x4^
 . ^svylc x2 + 2*x3^

 . ^svylogit disease gender age1 age2 age3^
 . ^svylc age2 - age1, or^

If the variables specified with the ^svymean^ , ^svytotal^, or ^svyratio^ command
contain missing values, you will have to use the ^complete^ option when you
first run the command:

 . ^svymean bp1 bp2, complete^
 . ^svylc bp1 - bp2^

(Note that ^svyreg^, ^svylogit^, and ^svyprobt^ always use only complete cases.) 

When you have ^by()^ subpopulations, ^svylc^ uses the syntax used by the
^test^ command with multiple equations:

 . ^svymean vitaminc, by(sex)^
 . ^svylc [vitaminc]Male - [vitaminc]Female^

For more than one ^by()^ variable, first use the ^show^ option to see the
labeling:

 . ^svymean vitaminc, by(sex race)^
 . ^svylc, show^
 . ^svylc svylc [vitaminc]1 - [vitaminc]2^

Also use ^show^ after ^svyratio^:

 . ^svyratio y1/x1 y2/x2^
 . ^svylc, show^
 . ^svylc [y1]x1 - [y2]x2^

 . ^svyratio y1/x1, by(race)^
 . ^svylc, show^
 . ^svylc [1]White - [1]Black^


Also see
--------

On-line:  help for @svymean@, @svyreg@, @svytest@