Low Volume Threshold
Two- and four-digit UoEs were only assessed where there was a meaningful level of data to be evaluated. An institution is only evaluated in ERA in a two- or four-digit discipline if the number of research outputs submitted reaches the low volume threshold.
For disciplines where citation analysis was used, the low volume threshold was 50 apportioned indexed journal articles. No evaluation was conducted for the FoR at a given institution if the submitted number of apportioned indexed journal articles over the six-year research outputs reference period was fewer than 50 in any two- or four-digit FoR.
For disciplines where peer review was used, the low volume threshold was 50 apportioned weighted outputs. For these disciplines, books were given an effective weighting of 5:1 compared with other research outputs. Books were weighted only for the purposes of determining the low volume threshold; in every other instance they were regarded as a single research output. Portfolios of works were counted as one output for the purposes of determining the low volume threshold. No evaluation was conducted for an FoR at a given institution where, over the six-year research outputs reference period, there were less than the equivalent of 50 apportioned weighted research outputs submitted.
For some FoRs at some institutions, there was insufficient research volume to undertake a valid analysis at the four-digit FoR level, but sufficient research volume at the two-digit FoR level. In these instances, evaluation took place at the two-digit FoR level only.
Where the low volume threshold was not met, the UoE for a given institution was automatically treated as ‘not assessed due to low volume’, and is reported as ‘n/a’. This means that data submitted on research outputs, research income, applied measures and esteem measures for the relevant two- or four-digit FoR for that institution was collected but not evaluated under ERA 2015. The institution, therefore, was not considered as research active for that discipline for the purposes of ERA 2015. However, the data submitted still contributed to the construction of the ERA benchmarks and all ERA data was aggregated for national-level reporting irrespective of whether any FoRs within a specific institution met the low volume threshold.