3.2 As part of the process of examining how best to support the legislative changes, the Inland Revenue considered options which would not involve using the NIRS 2 system, including clerical solutions, using other information technology systems, and deferring the work. Although there was scope to use other systems, they concluded that, in most cases, the alternative options would have required modifications to NIRS 2 anyway, and would have led to duplication of effort. Most of these alternatives were discarded, as were deferral and clerical solutions, which would have incurred significant costs or delays (Figure 5). Based on function point estimates at the time, this left NIRS 2 as the most practicable option for some 80 per cent of the work requirement.