Where cycling is concerned, the lack of representativity offered by the sample meant that data had to be taken from studies done in other cities, and a rate of 9 km/h was adopted (Bonnel & Caubel [16]).
Image cytometry was to be performed on 76 pretreatment biopsy sections (8 μm) with tumour representativity confirmed by our pathologist (GE) with corresponding HTX slides.
This qualifies the ability to ensure representativity and objectivity by using explicit methods.
Representativity was assessed by histopathologic analysis from the immediate vicinity (neighbour section) to the biopsy used for extraction of total RNA.
The issues for external validity include that the sample size was relatively small and all patients came from Paris, France; however representativity was increased by recruitment from both tertiary care and private practices and the patient characteristics are in keeping with usual data for these populations.
In the list of genes regulated by intracellular pathways, we found significant representativity of genes regulated by ABL, AMPKinase alpha 1 subunit (AMPKa1), calcium storage, cyclooxygenase 2 (COX2), glycosylphosphatidylinositol phospholipase D (GPI-PLD), JNK, PKA, RRM2B, Tuberous sclerosis 1 and 2 (TSC1/2), and regulator of translation PTEN.
Although this may have induced bias, for example because some GPs were more interested in communication than others, this is contradicted by the representativity of the participating GPs [ 31].
However, these models suffer limitations (incompleteness and lack of statistical representativity), which can be overcome by model averaging and fusion.
In order to ensure sample representativity, the samples were taken by experienced gynaecologists and gynaecological surgeons.
Other important strengths are the criterion-related study design, using an expert panel as a way of handling the problem of non-existing objective data for comparison, and the assessments of representativity, using different samples recruited by different sampling methods.
