Case ascertainment is calculated differently based on the type of team:
a) Routinely admitting acute teams
An estimated number of admissions and discharges in any one reporting period are provided to all routinely admitting teams. In England this expected figure is based upon historical Hospital Episode Statistics (HES coding) because current numbers are not available in real time. For Northern Ireland and Wales this is derived from previous data sources and on-going data submissions.
It is required that teams submit all stroke patients with a primary diagnosis of stroke. Case ascertainment is calculated based on the proportion of patient admissions (locked to 72 hours) AND proportion of discharges (locked to discharge or transferred to another team) against the expected number in any one reporting period. The average of these two percentages is then used for the overall case ascertainment banding. To ensure no downward adjustment of the overall SSNAP level teams must ensure that their case ascertainment band is ≥ 90%. 75% of the expected number of cases is the minimum required in order to receive named team results.
To view your current expected cases, follow this link once logged into the SSNAP webtool, and download "Expected cases".
Amending the expected number of cases for routinely admitting teams
The number of stroke patients seen over time may fluctuate particularly when a service undergoes reconfiguration. If a team’s number of cases varies by more than 10% then the SSNAP team may be able to adjust the expected number of cases. Where this applies teams are encouraged to contact the SSNAP helpdesk as soon as possible. Evidence - ordinarily supplied via a team’s information or coding department - of the total number of stroke cases coded as I61, I63 and I64 must be supplied for the previous 12 months. It is not possible to change the expected figure after a quarterly locking deadline.
b) Non-routinely admitting inpatient teams and non-inpatient teams
For non-routinely admitting teams, HES projections have not been used. A proxy has been generated comparing the number of patients arriving at a team with the number of patients leaving the team in a reporting period. Teams should always ensure that all discharges within a reporting period are locked prior to the quarterly locking deadline.
Click here to see how the SSNAP scoring is calculated and how case ascertainment can cause negative adjustment