An uncorrected estimation of the incidence as the ratio between the annual number of IS cases reported through the ESPED network and the number of children at risk (provided by the "Statistisches Bundesamt, the German Federal Office for Statistics, for 2006" [ 12]) might lead to under-estimation of IS incidence due to under-reporting of cases.
However, reports describe that poor documentation of the performed tasks by nurses might lead to under-reportage [ 31, 32].
As a potential drawback, this might lead to under- or over-fitting of the AR model and consequent erroneous dependencies.
Finally, spatial heterogeneity of prostate cancer might lead to under- or, rarely, overestimation of prostate cancer aggressive potential on diagnostic needle-biopsies.
The fact that we investigate upstream sequences for histone modifications might lead to under-estimate a putative 3metH3K9 modification in the sequences investigated for DNA methylation, and this results that RELB could be even more silenced than we proposed.
Second, the identification of respondents from within specific geographical distances to contracted facilities might lead to under- or over-representation of voucher users depending on how spread they are from the facilities.
This lack of evidence on the effectiveness of adjuvant chemotherapy in older patients and concerns about greater risks of adverse events might lead to under-treatment and increased lung cancer mortality among such patients with non-small cell lung cancer.
However, these control ccp experiments illustrate a rarely documented weakness of microarray experiments, namely the problem of false negative results that, due to over-stringent use of statistical analysis, might lead to under-estimation of the number of differentially expressed genes.
The EMR data may differ from other databases due to patients' stage and disease severity and clinic/provider specialization; this was noted specifically for prostate cancer, where treatment by urologists (rather than oncologists) providing less aggressive treatment might lead to under-representation of this tumor in the EMR population.
The differences in our findings compared to other studies may also reflect other methodological factors such as sample size, ascertainment of drinking behaviour by self-report questionnaire rather than interview (the latter might lead to under-reporting), number of binge episodes and levels of background drinking.
