What is fully conditional specification?
Fully conditional specification (FCS) imputes multivariate missing data on a variable-by-variable basis (Van Buuren et al. 2006; Van Buuren 2007a). The method requires a specification of an imputation model for each incomplete variable, and creates imputations per variable in an iterative fashion.
What is fcs regression?
With an FCS statement, the variables are imputed sequentially in the order specified in the VAR statement. For a continuous variable, you can use a regression method or a regression predicted mean matching method to impute missing values.
What is substantive model?
1. A theoretical model that provides a “working theory” of action for a specific context.
What is PROC MI?
The PROC MI statement invokes the MI procedure. Table 79.1 summarizes the options available in the PROC MI statement. displays both the missing data patterns and the group means in the table. NOMEANS. displays only the missing data patterns in the table.
What is conditional imputation?
It is a simple and appealing method; it uses all the data, and it separates the missing data part, which is handled by imputation, from the analysis part, which is done by complete data methods. We give two examples of well-known imputation procedures.
What is monotone missing pattern?
A missing data pattern is said to be monotone if the variables Yj can be ordered such that if Yj is missing then all variables Yk with k>j are also missing. This occurs, for example, in longitudinal studies with drop-out. If the pattern is not monotone, it is called non-monotone or general.
How do you impute in SAS?
Imputation in SAS requires 3 procedures. The first is proc mi where the user specifies the imputation model to be used and the number of imputed datasets to be created. The second procedure runs the analytic model of interest (here it is a linear regression using proc glm) within each of the imputed datasets.
What is substantive theory example?
The phenomena of dying, for example, is a substantive area and a substantive theory of this phenomenon is built from analysis within or among groups within the same substantive area. For example, the study of hospital wards where patients died at different rates could reveal substantive theory about dying.
What is substantive planning theory?
Substantive theory focuses on the substance/subject of urban planning: e.g., on city form, design, layout, on what makes a good city, etc. This simple distinction is, like most dichotomies, not absolute, and many theories combine both procedural and substantive elements.
What is Rubin’s rule?
Rubin´s Rules (RR) are designed to pool parameter estimates, such as mean differences, regression coefficients, standard errors and to derive confidence intervals and p-values. The t-test is used to estimate the difference in mean Tampascale values between patients with and without Radiation in the leg.
What is multivariate normal imputation?
Multivariate normal imputation MVNI is a joint modelling approach to imputation where all variables in the imputation model are assumed to follow a multivariate normal distribution. Initially, missing values are imputed based on assumed starting parameter values for the multivariate normal distribution.