Because these simulations cannot be performed in multilevel data, the unilevel equivalent of the n of the multilevel data set was calculated using the following formulaes [ 40]. (1) MF = 1 + 9 – 1 * 0.6 = 5.8 (2) uen = 51 * 9 / 5.8 = 79 In which 9 is the number of assessments per person, 51 is the number of persons and 0.6 is the intra class correlation.
Since it could be shown that individual and institutional data complement each other in the circumstances of healthcare-associated infections, 23 a multilevel data set covering all patients with a positive BC in Thuringia will be established and can be used for further investigation (figure 3).
Depending on data requirements, models will be developed using fixed-entry binary logistic regression, multilevel modelling and multiply imputed data sets, to compare outputs based on statistical technique.
> -wrap-foot> We applied nonparametric multilevel LMMs to 2 longitudinal data sets from Tanzanian and Gambian communities with low baseline trachoma prevalence before and after a round of mass azithromycin administration.
25 Studies have shown that methods assuming normality can be quite robust even when costs are highly skewed; however, within this study it is difficult to know whether the precision of cost estimates would have improved had it been possible to estimate an aggregated multilevel generalised gamma model across MI data sets.
Multilevel linear regression with imputed data (20 data sets).
This caveat is offered as a caution to researchers using multilevel logistic regression in conjunction with small data sets; under these conditions researchers can expect to encounter convergence problems, large biases in their model estimates and inadequate statistical inference procedures.
Although continuous time models remain the most popular for survival analysis, discrete-time methods have several advantages, especially in the multilevel framework when using large public health data sets [ 33, 34].
As observations were clustered within individuals for both data sets (symptom level and coping level), multilevel random regression analyses were conducted using the STATA XTGEE (binary coping variable) and XTREG (continuous distress and control variables) routines.
