Figure 1 is a line chart showing variations in actual numbers when NNDSS data is compared with AMRLN data. The gap has been consistently around 22-30%. Causes for the gap include: Differences in the reporting schedule (AMRLN is by date of specimen collection whilst NNDSS is by date of notification); and NNDSS includes cases where no laboratory testing was conducted and includes young children being diagnosed by X-ray and clinical assessment, and cases where wither no sample was submitted for laboratory investigations or the submitted sample was unsuitable for testing.