COMPASS > COMPASS Prescribing Report > Patient Denominators
In order to make relevant comparisons between practices or groups of practices, each practice’s population must be appropriately weighted. Practice populations are weighted using the Northern Ireland Prescribing Unit (NIPU) benchmark.
The NIPU benchmark is a method for both distributing and benchmarking prescribing resources. It was derived by the Health and Social Services Executive in consultation with HSS Boards, the Department of General Practice at QUB and other academic advisors. The NIPU consists of three elements namely population size, relative age/sex structure and additional need due to higher morbidity/deprivation. Two practices may have a similar size and age/sex structure, but one may have an additional “need” for prescribing resources due to morbidity and/or socio-economic reasons. The age/sex weights are as outlined below.
|
Age Group |
Males |
Females |
|
0-1 |
1.51 |
1.29 |
|
2-4 |
1.51 |
1.29 |
|
5-15 |
1.13 |
1.00 |
|
16-24 |
1.24 |
1.37 |
|
25-44 |
2.03 |
2.80 |
|
45-59 |
4.61 |
5.77 |
|
60-64 |
7.26 |
8.53 |
|
65-74 |
9.64 |
9.66 |
|
75+ |
11.21 |
11.59 |
|
Temp. Res |
0.50 |
0.50 |
The interpretation of the age/sex weights is that an elderly woman aged 75 or over is expected to cost over 11 times the cost of a female aged 5-15. The number of males and females within each group is multiplied by the relevant weight, totalled and multiplied by an additional needs factor. The table below shows an example of how the number of NIPUs is calculated for a practice.
|
|
Patient Numbers |
|
| |
|
Age Group |
Males |
Females |
Male NIPUs |
Female NIPUs |
|
0-1 |
113 |
103 |
113 x 1.51 = 171 |
103 x 1.29 = 133 |
|
2-4 |
160 |
178 |
160 x 1.51 = 242 |
178 x 1.29 = 230 |
|
5-15 |
653 |
649 |
653 x 1.13 = 738 |
649 x 1 = 649 |
|
16-24 |
544 |
592 |
544 x 1.24 = 675 |
592 x 1.37 = 811 |
|
25-44 |
1642 |
2204 |
1642 x 2.03 = 3333 |
2204 x 2.8 = 6171 |
|
45-59 |
715 |
719 |
715 x 4.61 = 3296 |
719 x 5.77 = 4149 |
|
60-64 |
148 |
189 |
148 x 7.26 = 1074 |
189 x 8.53 = 1612 |
|
65-74 |
312 |
392 |
312 x 9.64 = 3008 |
392 x 9.66 = 3787 |
|
75+ |
171 |
399 |
171 x 11.21 = 1917 |
399 x 11.59 = 4624 |
|
Temp. Res |
0 |
0 |
0 x 0.5 = 0 |
0 x 0.5 = 0 |
|
Total |
4458 |
5425 |
14453 |
22166 |
|
|
|
|
|
|
|
Needs Index = 0.891 |
|
Total NIPUs = (14453 + 22166) * 0.891 = 32627 | ||