Furthermore, in order to retain a final model, a two-by-two interaction terms were checked for variables that remained statistically significant in the pre-final model.
27 We checked for variables which were unequally distributed across arms, and conducted an adjusted analysis accordingly.
But whether this is of relevance for this analysis remains questionable (an association of positive responses and specialty could not be found; checked for variables 3, 4, and, 5; data not shown).
The software provided to GPs for data entry offers automatic checks for variables congruence (e.g. an information related to the number of daily smoked cigarettes could not refer to a non-smoker) and alerts GPs to missing data.
Non-response bias may be another problem but its relevance seems as well questionable because an association between proportions of positive answers and sex, work place, or location of work place could not be found (checked for variables 3, 4, and 5; data not shown) (see also [ 22]).
1 J.L. Boore, personal communication; 2 [ 88] The 20 sequences obtained for both F and M genomes were aligned (not shown), and, after checking for variable sites, used to design sex-specific primers to amplify the entire mitochondrial genome in two overlapping fragments by long PCR reactions.
Thus it is believed that the inaccuracies in this survey are rather a problem of careless reading/answering (Which again might have been resulted from the long questionnaire or busy respondents although an association between the weekly hours of work and positive responses could not be found. Checked for variable 4; data not shown) or a failure in self-perception/overestimation of competency.
Statistical interactions between variables were checked for all variables.
The first data check looks for variable names that may indicate common PHI elements such as personal identifiers, birth dates, health encounter dates and death dates.
Validity checks were made concurrent with data entry in the electronic case record form, including plausibility checks for each variable and between variables.
