age at diagnosis which, by definition of childhood cancer, is supported on the
interval (time in years). The number of cases was 409. However, for three cases the value of
was not available, so we only consider the
children who report complete information.
Because of the interval sampling, the age at diagnosis
is doubly truncated by the pair
, where the right‐truncation variable
is the time in years from birth (date of onset,
) to 31 December 2003, and
. The
triplets
,
, with the values observed for
were reported in Moreira and de Uña‐Álvarez (2010), while de Uña‐Álvarez (2020) included the cancer group in the statistical analysis. Ordinary descriptive statistics can be applied to the information gathered along this 5 year long window to compute, for instance, the average age at cancer diagnosis. However, if the goal is to describe the population of children eventually developing cancer, the double truncation issue should be acknowledged and properly corrected, so potential biases are avoided.
Interestingly, the observed values for
range between
and 14.5 (years); equivalently, the observed values for
range between 0.5 and 19.5. This means that the lower and upper endpoints of
age at diagnosis which, by definition of childhood cancer, is supported on the 
