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REPLICATE WEIGHTS TECHNIQUE
Derivation of replicate weights 5 The deleteagroup jackknife method of replicate weighting was used to derive weights, through the following process:
Application of replicate weights 6 As noted above, replicate weights enable variances of estimates to be calculated relatively simply. They also enable unit record analyses such as chisquare and logistic regression to be conducted, which take into account the sample design. 7 Replicate weights for any variable of interest can be calculated from the 250 replicate groups, giving 250 replicate estimates. The distribution of this set of replicate estimates, in conjunction with the full sample estimate (based on the general weight) is then used to approximate the variance of the full sample. 8 The formulae for calculating the Standard error (SE), relative standard error (RSE) and 95% Margin of Error (MoE) of an estimate using this method is shown below. where:
9 The RSE(y) = SE(y)/y*100. 10 The 95% MoE(y)=SE(y)*1.96. 11 This method can also be used when modelling relationships from unit record data, regardless of the modelling technique used. In modelling, the full sample would be used to estimate the parameter being studied, such as a regression coefficient. The 250 replicate groups would be used to provide 250 replicate estimates of the survey parameter. The variance of the estimate of the parameter from the full sample is then approximated, as above, by the variability of the replicate estimates. Availability of RSEs calculated using replicate weights 12 Actual RSEs were used in the summary publication released from this survey. The RSEs for estimates published in the National Aboriginal and Torres Strait Islander Social Survey, 2014–15 (cat no. 4714.0) are available in spreadsheet format from the Downloads tab. The RSEs in the spreadsheets were calculated using the replicate weights methodology. Availability of MoEs calculated using replicate weights 13 Actual MoEs for proportion estimates have been calculated in the summary publication released from this survey. The MoEs for estimates published in the National Aboriginal and Torres Strait Islander Social Survey, 2014–15 (cat no. 4714.0) are available in spreadsheet format from the Downloads tab. The MoEs in the spreadsheets were calculated using the replicate weights methodology. Reliability of estimates 14 For further information relating to the reliability of estimates, including the calculation of relative standard errors, margins of error, comparison of proportions, significance testing, and age standardisation, see Technical Note: Reliability of estimates from the National Aboriginal and Torres Strait Islander Social Survey, 2014–15 (cat no. 4714.0). Document Selection These documents will be presented in a new window.
