We therefore also controlled for clustered sampling within household using unique household identifiers that produced Huber/White/sandwich robust variance estimators that allowed for within-household dependence [38].
When within-unit dependence of the outcome is relatively large, such designs can be much more efficient than parallel group studies with the same number of units.
To avoid biases caused by within-sample dependence, we estimated the significance of Kendall's tau by randomly permuting the expression values among the TFs and our results remain statistically significant.
Since measurements in one woman are expected to be much more similar than measurements in different women, regression and ANOVA require an extension that incorporates the within-subject dependence.
By fitting an ordinary ORM with robust standard errors for clustered data instead of fitting a variance components model (a multilevel model for ordinal responses), we were treating the within-cluster dependence as a "nuisance" and not as a phenomenon that we were interested in [36].
In particular, GEE models allowed us to assess the significance of main and interactive effects of 'Type of tDCS', 'Site of tDCS', 'Gender,' 'Type of dilemma' and 'Time' as predictors (factors) on utilitarian responses and RTs measures, taking into account within-subject dependence.
The method is a development of regression and ANOVA, allowing a model of "within-subject dependence".
The intracluster correlation coefficient (ICC) is the statistical measure of this within-cluster dependence.
This within-family dependence was taken into account in all of the primary analyses.
The models assumed a γ distribution of the county-level random intercept, accounting also for within-county dependence [ 20].
