The 'repeated cross section' measures refer to the fact that multiple cross sectional measures are made with different patients in each cluster for each of the sampling time periods [ 55], as recently used in surgical patients across three hospitals [ 58].
However, it is important to note that although the longitudinal measure of adherence provided a more complete picture of women's non-use of gel than cross sectional measures, it was still constrained by relying on self-reported or proxy measures and may well over estimate true adherence.
First, we use a measure of job strain that better represents individuals' long-term work conditions rather than the one-period (cross sectional) measure.
Moreover, most previous studies use a one-period (cross sectional) measure of job strain which may only reflect temporary effects, or small samples that are not necessarily representative of the population, while other studies focus only on some stressful occupations.
On the other hand, three-dimensional measurements, based on three cross-sectional measures [ 6, 11, 12], are a time efficient method to assess BMLs with good construct validity but include a lot of healthy bone.
They identify 16 loci newly associated with variation in two cross-sectional measures of lung function, used to define airway obstruction and to grade the severity of obstruction.
At the same time the availability of new micro-data sets (on individuals) and the possibility to carry out record linkage allow to calculate "traditional" cross-sectional measures of integration with a longitudinal approach.
These results suggest that variation in longitudinal change of some brain volume measures may have different underlying genetic and environmental architecture from variation in repeat cross-sectional measures, which could have implications for intervention strategies for age-related illness associated with brain morphology.
First, variability of health status as experienced by individuals is only crudely measured by cross-sectional measures such as the standard deviation of age at death.
In other words, the crucial difference between mobility studies and dynamic comparisons of cross-sectional measures of inequality and poverty is that mobility studies can unveil the intertemporal anonymity that accompanies cross-sectional studies.
Since the mortality associated with CD28 down-regulation per se appears to be independent of concurrent physiologic measures, the unrecognized inclusion of patients with significant proportions of CD4+CD28null cells in earlier analyses may have confounded assessments based solely on cross-sectional measures of pulmonary function (i.e., increase the "noise to signal ratio").
