Table 4. Scenarios using a unique hospital case-mix distribution.

		Significant HSMR change
Scenario	Number of hospitals changing category	By 1 hospital	By 2–5 hospitals	By more than 5 hospitals	By 1 other year	By more than 1 year
2	10 (7)	2	3	5	N.A.	N.A.
4	2 (2)	N.A.	N.A.	N.A.	2	0
6	35 (13)	6	4	25	N.A.	N.A.
8	3 (1)	N.A.	N.A.	N.A.	0	3

In scenario 2 and 6 the HSMR is recalculated using the distribution of the case-mix variable under study of a single hospital. In these scenarios for each hospital 60 HSMRs are recalculated. In scenario 4 and 8 the HSMR is recalculated using the distribution of the case-mix variable under study of another year. In these scenarios for each hospital three HSMRs are recalculated. In the second column the numbers of hospitals are shown for which the recalculated HSMR crosses a ‘control limit’. In brackets: the number of hospitals for which the HSMR lies close to a control limit (within 2 HSMR points). Columns 3 to 5 show an overview of the number of hospitals whose case-mix distribution changes the HSMR of a hospital significantly. Columns 6 and 7 show an overview of the years where the differences in case-mix distribution change the HSMR of a hospital significantly.