Well, in Quebec, birth weight data are reliable since around 1976. As a result of the phase during the transition to the metric system, we are not always entirely sure whether weight data entries are in pounds or kilograms, hence the importance of having quality data. Sometimes, for example, we don't know whether the weight indicated was three pounds or three kilograms.
From 1976 onward, the data are reliable. This enables us to track people up to the present day. Since 1987 in Quebec, we have reliable data from MED‑ECHO on the history and diagnoses made during hospitalization. However, we don't have reliable data on visits to the doctor. If someone went to the doctor's office because of diabetes, an ear infection or for any other reason, we have only a single diagnosis, the one drawn from the database.
There are areas that need improvement; hence the importance of data.