While standardized forms (such as birth and death certificates) are important and very useful, many times the information listed on the certificate may not be complete. List the reasons why this happens.

What will be an ideal response?

For death certificates, the person recording the items  may not know the details of the decedent's personal history to correctly record risk factors as listed on the certificate (e.g., smoking, occupation).  Likewise for birth certificates, some of the information requested on the form is not available prior to the form being sent forward for inclusion in the national database. Examples are birth defects that are not identified until later. Although birth and death certificates are collected within days of the event and submitted so that statistics are available in a few months, changes or alterations to the certificates or additional data items that were not completed initially can be sent later. Some data sets, such as cancer registries, may not have the complete information on a subject (including pathology reports and initial treatment) available until several months after the diagnosis.