submitted multiple times in the same UoA by the same institution.

Some institutions can have separate submission headings in the same UoA to differentiate more fine-grained subjects. For example, Goldsmiths’ College separately submits publications for Music and Theatre & Performance in the overall UoA of Music, Drama, Dance & Performing Arts. The results of such separate submissions are also announced separately, and we therefore also consider them to be separate submissions.

We consider citations coming from publications up to and including 2014, which is realistic if metrics had actually been used during the REF itself. For this reason, we exclude $365$ publications that were officially published after 2014 (although they may have already been available online). We use about $4\,000$ micro-level fields constructed algorithmically on the basis of citation data [@Waltman2012; @Ruiz-Castillo2015] to perform field normalisation. Citations are normalised on the basis of publication year and field, relative to all publications covered in the WoS.

We calculate how many $4^*$ publications correspond to how many top $10\%$ publications per UoA (see Table \[tab:estimate\_b\]). This can differ quite substantially from one UoA to another. For example, Clinical Medicine shows $0.57$ $4^*$ publications per top $10\%$ publication, whereas Mathematical Sciences show $1.18$ 