The SURVEYPHREG Procedure

REPWEIGHTS Statement

  • REPWEIGHTS variables </ options>;

The REPWEIGHTS statement names variables that provide replicate weights for replication variance estimation, which you request with the VARMETHOD=BOOTSTRAP, VARMETHOD=BRR, or VARMETHOD=JACKKNIFE option in the PROC SURVEYPHREG statement. If you do not provide a REPWEIGHTS statement for VARMETHOD=BRR or VARMETHOD=JACKKNIFE, then PROC SURVEYPHREG constructs replicate weights for the analysis. For more information, see the sections Balanced Repeated Replication (BRR) Method and Jackknife Method. For VARMETHOD=BOOTSTRAP, you must specify the REPWEIGHTS statement to provide replicate weights. For more information, see the section Bootstrap Method.

Each REPWEIGHTS variable should contain the weights for a single replicate, and the number of replicates equals the number of REPWEIGHTS variables. The REPWEIGHTS variables must be numeric, and the variable values must be nonnegative numbers.

If you provide replicate weights with a REPWEIGHTS statement, you do not need to specify a CLUSTER or STRATA statement. If you use a REPWEIGHTS statement and do not specify the VARMETHOD= option in the PROC SURVEYPHREG statement, the procedure uses VARMETHOD=JACKKNIFE by default.

If you specify a REPWEIGHTS statement but do not include a WEIGHT statement, PROC SURVEYPHREG uses the average of each observation’s replicate weights as the observation’s weight.

You can specify the following options in the REPWEIGHTS statement after a slash (/):

JKCOEFS=jackknife-coefficient-specification

specifies jackknife coefficients for VARMETHOD=JACKKNIFE. The default value for the jackknife coefficient is left-parenthesis upper R minus 1 right-parenthesis slash upper R, where R is the total number of replicates. You can specify an alternative value with one of the following three forms:

JKCOEFS=value

specifies a single jackknife coefficient for all replicates. The coefficient value must be a nonnegative number.

JKCOEFS=(values)

specifies jackknife coefficients for VARMETHOD=JACKKNIFE, where each coefficient corresponds to an individual replicate identified by a REPWEIGHTS variable. You can separate values with blanks or commas. The coefficient values must be nonnegative numbers. The number of values must equal the number of replicate weight variables named in the REPWEIGHTS statement. List these values in the same order in which you list the corresponding replicate weight variables in the REPWEIGHTS statement.

JKCOEFS=SAS-data-set

names a SAS data set that contains the jackknife coefficients for VARMETHOD=JACKKNIFE. You provide the jackknife coefficients in the JKCOEFS= data set variable JKCoefficient. Each coefficient value must be a nonnegative number. The observations in the JKCOEFS= data set should correspond to the replicates that are identified by the REPWEIGHTS variables. Arrange the coefficients or observations in the JKCOEFS= data set in the same order in which you list the corresponding replicate weight variables in the REPWEIGHTS statement. The number of observations in the JKCOEFS= data set must not be less than the number of REPWEIGHTS variables.

See the section Jackknife Method for details about jackknife coefficients.

REPCOEFS=replication-coefficient-specification

specifies replicate coefficients for replication methods. When you specify VARMETHOD=JACKKNIFE, the default value for the replicate coefficient is left-parenthesis upper R minus 1 right-parenthesis slash upper R, where R is the total number of replicates. When you specify VARMETHOD=BOOTSTRAP or VARMETHOD=BRR, the default value for the replicate coefficient is 1 slash upper R.

For VARMETHOD=BOOTSTRAP or VARMETHOD=JACKKNIFE, you can specify one of the following three replication-coefficient-specifications:

REPCOEFS=value

specifies a single replicate coefficient for all replicates, where value must be a nonnegative number.

REPCOEFS=(values)

specifies a list of replicate coefficients, where each coefficient corresponds to an individual replicate that is identified by a REPWEIGHTS variable. You can separate values with blanks or commas. The coefficient values must be nonnegative numbers. The number of values must equal the number of replicate weight variables specified in the REPWEIGHTS statement. List these values in the same order in which you list the corresponding replicate weight variables in the REPWEIGHTS statement.

REPCOEFS=SAS-data-set

names a SAS-data-set that contains the replicate coefficients. You must provide the replicate coefficients in a variable named Coefficient or RepCoefficient in the SAS-data-set. Each coefficient value must be a nonnegative number. The observations in the SAS-data-set should correspond to the replicates that are identified by the variables that are specified in the REPWEIGHTS statement. Arrange the coefficients or observations in the SAS-data-set in the same order in which you list the corresponding replicate weight variables in the REPWEIGHTS statement. The number of observations in the SAS-data-set must not be less than the number of variables specified in the REPWEIGHTS statement.

For more information about replication coefficients, see the section Replicate Weights Method.

Last updated: December 09, 2022