Although recall of a medical contact was good, there were systematic errors in the reported frequency of physician visits (under-reported) and hospital nights (over-reported).
Although diet records with notebooks and scales can be more detailed and precise than standardised food frequency questionnaires, results from surveys of food intake have low reproducibility and, in particular, there are systematic errors in underreporting energy intake [ 22].
Even if there are systematic errors in the quantitation (i.e., if true protein copies per cell are all threefold higher), the fitting parameters for our mass-action model (see below) will be uniformly scaled but the overall interpretation of the model will be unchanged.
However, we do not believe that there were systematic errors with differences in fracture ascertainment between the groups.
Although ethnic differences have yet to be reported, systematic errors in measurement may also explain the variation.
Even though it is not feasible for us to perform a comprehensive evaluation of the quality of the data in each experiment, a meta-analysis is in its essence a technique to eliminate poor quality data and hence we are confident that there are no systematic errors in our analysis that artificially originate false results.
From the design history of all of the test images, it is clear that there are no systematic errors in either the translation symmetries or the site symmetries within all unit cells throughout all of the synthetic test images.
This type of bias is considered to be a systematic error in self-reporting measures resulting from the desire of respondents to avoid embarrassment and project a favorable image to others (Fisher 1993).
Because the position of celestial bodies changes with the time of day due to the Earth's rotation, the time of these calibration observations must be accurately known, or else there will be a systematic error in the measurements.
Secondly, it may be a systematic error in female respondents, i.e. they may be shy to discuss their knowledge about sex education skills rather than lack knowledge.
