pool.scalar {mice} | R Documentation |
Pools univariate estimates of m repeated complete data analysis
pool.scalar(Q,U)
Q |
A vector of univariate estimates of m repeated complete data analyses. |
U |
A vector containing the corresponding m variances of the univariate estimates. |
The function averages the univariate estimates of the complete data model, computes the total variance over the repeated analyses, and computes the relative increase in variance due to nonresponse and the fraction of missing information.
Returns a list with components
m |
The number of imputations |
qhat |
The m univariate estimates of repeated complete data analyses |
u |
The corresponding m variances of the univariate estimates |
qbar |
The pooled univariate estimate, formula (3.1.2) Rubin (1987). |
ubar |
The mean of the variances, formula (3.1.3) Rubin (1987). |
b |
The within imputation variance, formula (3.1.4) Rubin (1987). |
t |
Total variance of the pooled estimated, formula (3.1.5) Rubin (1987). |
r |
Relative increase in variance due to nonresponse, formula (3.1.7) Rubin (1987). |
df |
Degrees of freedom for t reference distribution, formula (3.1.6) Rubin (1987). |
f |
Fraction missing information due to nonresponse, formula (3.1.10) Rubin (1987). |
Karin Groothuis-Oudshoorn and Stef van Buuren, 2009
Rubin, D.B. (1987). Multiple Imputation for Nonresponse in Surveys. New York: John Wiley and Sons.
imp <- mice(nhanes) m <- imp$m Q <- rep(NA,m) U <- rep(NA,m) for (i in 1:m) { Q[i] <- mean(complete(imp,i)$bmi) U[i] <- var(complete(imp,i)$bmi) } pool.scalar(Q,U) #pool.scalar(Q,U) #$m #[1] 5 # #$qhat #[1] 26.764 26.748 27.024 27.340 26.436 # #$u #[1] 17.85490 19.11677 20.61440 21.05750 15.16990 # #$qbar #[1] 26.8624 # #$ubar #[1] 18.76269 # #$b #[1] 0.1147008 # #t #[1] 18.90033 # #$r #[1] 0.007335885 # #$df #[1] 75422.96 # #$f #[1] 0.007308785 #