Also, especially after the first 2 years of the registration, completeness of reporting by the different hospitals is highly consistent, with only a few units reporting less than 90% of cases thus reducing the risk of skewed results due to different reporting rates.
Primary outcome was registration of the reported test accuracy study.
Registration in the Public Health Information System of reported cases, age, sex, serological status, hospital admission, measles vaccination status and risk group from March, 1st 2009 to September, 1st 2011.
In most studies, and particularly in the large IARC study [ 6] the conventional indexes of quality of registration were reported to have been constant over the considered period.
The proportion of participants recruited where a transfer of registration was reported (and hence they received the initial flyer), without any further e-mail or postal contact, was similar throughout the project at 1.3-1.6 1.3-1.6
The modified OFM based on image intensity gradient was utilized for deformable image registration and the accuracy of registration was reported in previous studies [ 18– 20].
In table 3 the crude IRs for the first (0 - 18 months) and the second (19 - 36 months) period of registration are reported.
A validation study of the Taiwanese birth registration data reported a low percentage of missing information (1.6%) and good validity (sensitivity and specificity were 92.8% and 99.6%, respectively) and reliability (Cohen's k-statistic was 0.92) for preterm birth (< 37 weeks of gestational age) (Lin et al. 2004).
The studies conducted in the United Kingdom suffer from the same limitations, namely the possibility that misclassification of exposure could have decreased the relative risk estimates to some extent ; on the other hand, there are several uncertainties related to the quality of reporting and registration of congenital malformations.
The flow of information and timeliness has previously been studied in detail [ 16], and the median delay between diagnosis and registration of the report in EpiArk is 1 2 weeks.
